3713: RB 2.0.12 with Hg: new, empty file in diff causes diff viewer to fail to display different file

bruce*****@gmai***** (Google Code) (Is this you? Claim this profile.)
What version are you running?

What's the URL of the page containing the problem?

What steps will reproduce the problem?
1. Create a review request that includes a new, empty file
2. View the diff in Review Board

What is the expected output? What do you see instead?
All changed files should be displayed, and the new file should be listed.  Instead, the new file isn't listed, and the file that did exist and had changes is shown with an error ('patch failed').

What operating system are you using? What browser?
Windows 8.1 Update with Opera 26.

Please provide any additional information below.

Patches posted with "hg postreview" and "rbt post" (RBTools 0.6.2) both fail.
Patches generated in extended git format and uploaded via the Web interface cause all files with changes to be displayed with an error that the file couldn't be found.

The error displayed in the diff viewer is:
 Exception: The patch to 'dir/file.html' didn't apply cleanly. The temporary files have been left in '/tmp/reviewboard.IYX1_L' for debugging purposes.
`patch` returned:

Looking in /tmp/reviewboard.IYX1_L, file.html.diff is correct except it has trailing content from the new file:

diff --git a/dir/file.html b/dir/file.html
--- a/dir/file.html
+++ b/dir/file.html
@@ -44,6 +44,9 @@
+ new_line4
+ new_line5
+ new_line6
diff -r 12345 -r 67890 dir\a_new_file
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/dir/a_new_file       Fri Jan 09 21:57:53 2015 -0700