Issue 1151: http://code.google.com/p/reviewboard/issues/detail?id=1151

What steps will reproduce the problem?
1. I have 2 different subversion repositories. They have the same repository UUID (same server, different addresses)
2. Both repositories are created in review-board as repository 1 and 2
3. post-review in a folder that belongs to repository 2
4. post-review incorrectly detects the file as belonging to repository 1

What is the expected output? What do you see instead?
post-review detects the correct repost

What operating system are you using? What browser?
post-review on winxp, python 2.5.1 
review-board server on ubuntu 9.04

Please provide any additional information below.
The problem seems to be that only relative paths are looked at, and that it is not checked if the repos urls are the same. I cannot really figure out what the _get_relative_path on line 196 i ment to do. Simply removing the call to this function and replacing it with a check on he repos url. Not sure if this is the correct way to do this, but it seems to work?