What version are you running?
0.7.9
What steps will reproduce the problem?

In a feature branch, do svn merge -c <revision> <trunk url>
rbt post --svn-show-copies-as-adds=y
In a clean checkout of feature branch, do rbt patch <review request id>


What is the expected output? What do you see instead?
Expected Result: Should be able to patch the diff.

Actual Result: rbt patch failed. 

Error is:

svn: E000021: Can't move '/home/devops/jenkins_slave/workspace/ReviewBoard/ReviewBoard_Commit/FortiSwitchOS v3.00/svn-qdo28p' to '/home/devops/jenkins_slave/workspace/ReviewBoard/ReviewBoard_Commit/FortiSwitchOS v3.00/3.5': Is a directory
What operating system are you using?
Ubuntu 14.04
Attach the debug out from the command.
```

$ rbt patch --debug <args>

Debug log attached

Please provide any additional information below.
When svn merge -c is used, when rbt post, it somehow knows it's a merge so rbt modifies the file path. For example, the diff from rbt post would look something like this:
Index: /ABC/branches/3.x/3.5/trunk/cooked/cert/802.1x.crt
--- /ABC/trunk/cooked/cert/802.1x.crt   (nonexistent)

+++ /ABC/branches/3.x/3.5/trunk/cooked/cert/802.1x.crt  (working copy)
Somehow rbt knows it's merge from trunk to 3.5 branch, so it modified the path in the diff. When I run rbt patch, then it will fail. 
Eventually I had to manually modify the diff file to the following for it to work:

Index: /ABC/branches/3.x/3.5/trunk/cooked/cert/802.1x.crt

===================================================================

--- /ABC/branches/3.x/3.5/trunk/cooked/cert/802.1x.crt  (nonexistent)

+++ /ABC/branches/3.x/3.5/trunk/cooked/cert/802.1x.crt  (working copy)