What version are you running?
3.0.5

What's the URL of the page containing the problem?
https://rb.eng.pulse-origin.com/admin/db/scmtools/repository/44/

What steps will reproduce the problem?

Go to ReviewBoard administration interface
In "MANAGE" go to "Repositories" and edit a repository
In "BUG TRACKER" uncheck "Use hosting service's bug tracker" and configure a custom bug tracker with: Type=JIRA and JIRA URL=https://jira.eng.pulse-origin.com
Save settings.


What is the expected output? What do you see instead?
I expect to see my new configuration saved, instead I see:
Something broke! (Error 500)
It appears something broke when you tried to go to here. This is either a bug in Review Board or a server configuration error. Please report this to your administrator. 
In ReviewBoard logs I get:

2018-03-26 13:09:48,594 - ERROR -  - root - Failed to generate %(jira_url)s/browse/%%s field for hosting service JIRA using {u'hosting_account_username': u'', u'hosting_url': u''}: Missing key u'jira_url'

Traceback (most recent call last):

  File "/usr/local/lib/python2.7/dist-packages/ReviewBoard-3.0.5-py2.7.egg/reviewboard/hostingsvcs/service.py", line 1090, in get_bug_tracker_field

    return bug_tracker_field % field_vars

KeyError: u'jira_url'

2018-03-26 13:09:48,595 - ERROR - None - ddejean - /admin/db/scmtools/repository/44/ - djblets.log.middleware - Exception thrown for user ddejean at https://rb.eng.pulse-origin.com/admin/db/scmtools/repository/44/
u'Internal error when generating %(jira_url)s/browse/%%s field (Missing key "u\'jira_url\'"). Please report this.'

Traceback (most recent call last):

  File "/usr/local/lib/python2.7/dist-packages/Django-1.6.11.7-py2.7.egg/django/core/handlers/base.py", line 112, in get_response

    response = wrapped_callback(request, callback_args, callback_kwargs)

  File "/usr/local/lib/python2.7/dist-packages/Django-1.6.11.7-py2.7.egg/django/contrib/admin/options.py", line 465, in wrapper

    return self.admin_site.admin_view(view)(*args, kwargs)

  File "/usr/local/lib/python2.7/dist-packages/Django-1.6.11.7-py2.7.egg/django/utils/decorators.py", line 99, in _wrapped_view

    response = view_func(request, args, kwargs)

  File "/usr/local/lib/python2.7/dist-packages/Django-1.6.11.7-py2.7.egg/django/views/decorators/cache.py", line 52, in _wrapped_view_func

    response = view_func(request, *args, kwargs)

  File "/usr/local/lib/python2.7/dist-packages/Django-1.6.11.7-py2.7.egg/django/contrib/admin/sites.py", line 198, in inner

    return view(request, args, kwargs)

  File "/usr/local/lib/python2.7/dist-packages/Django-1.6.11.7-py2.7.egg/django/utils/decorators.py", line 29, in _wrapper

    return bound_func(*args, kwargs)

  File "/usr/local/lib/python2.7/dist-packages/Django-1.6.11.7-py2.7.egg/django/utils/decorators.py", line 99, in _wrapped_view

    response = view_func(request, args, kwargs)

  File "/usr/local/lib/python2.7/dist-packages/Django-1.6.11.7-py2.7.egg/django/utils/decorators.py", line 25, in bound_func

    return func(self, *args2, kwargs2)

  File "/usr/local/lib/python2.7/dist-packages/Django-1.6.11.7-py2.7.egg/django/db/transaction.py", line 371, in inner

    return func(*args, kwargs)

  File "/usr/local/lib/python2.7/dist-packages/Django-1.6.11.7-py2.7.egg/django/contrib/admin/options.py", line 1244, in change_view

    if form.is_valid():

  File "/usr/local/lib/python2.7/dist-packages/ReviewBoard-3.0.5-py2.7.egg/reviewboard/scmtools/forms.py", line 1171, in is_valid

    if not super(RepositoryForm, self).is_valid():

  File "/usr/local/lib/python2.7/dist-packages/Django-1.6.11.7-py2.7.egg/django/forms/forms.py", line 129, in is_valid

    return self.is_bound and not bool(self.errors)

  File "/usr/local/lib/python2.7/dist-packages/Django-1.6.11.7-py2.7.egg/django/forms/forms.py", line 121, in errors

    self.full_clean()

  File "/usr/local/lib/python2.7/dist-packages/ReviewBoard-3.0.5-py2.7.egg/reviewboard/scmtools/forms.py", line 941, in full_clean

    super(RepositoryForm, self).full_clean(*args, kwargs)

  File "/usr/local/lib/python2.7/dist-packages/Django-1.6.11.7-py2.7.egg/django/forms/forms.py", line 274, in full_clean

    self._clean_form()

  File "/usr/local/lib/python2.7/dist-packages/Django-1.6.11.7-py2.7.egg/django/forms/forms.py", line 300, in _clean_form

    self.cleaned_data = self.clean()

  File "/usr/local/lib/python2.7/dist-packages/ReviewBoard-3.0.5-py2.7.egg/reviewboard/scmtools/forms.py", line 977, in clean

    self._clean_bug_tracker_info()

  File "/usr/local/lib/python2.7/dist-packages/ReviewBoard-3.0.5-py2.7.egg/reviewboard/scmtools/forms.py", line 831, in _clean_bug_tracker_info

    plan, new_data)

  File "/usr/local/lib/python2.7/dist-packages/ReviewBoard-3.0.5-py2.7.egg/reviewboard/hostingsvcs/service.py", line 1101, in get_bug_tracker_field

    'key': e,

KeyError: u'Internal error when generating %(jira_url)s/browse/%%s field (Missing key "u\'jira_url\'"). Please report this.'

What operating system are you using? What browser?
OS: Debian 9 with KDE

Browser: Firefox 59.0 64 bits

Please provide any additional information below.
If I put the same bug tracker configuration in a new repository, I can't submit, the UI reports JIRA URL field to be missing.