Fix unit tests for diff filenames.

My fix to strip off leading slashes in filenames broke one of the unit tests
for post-commit review request creation. The fix is just trivially updating the
expected result.

Testing done: Ran unit tests.
Google Code post-receive hook

This is a Google Code post-receive hook that will automatically close review
requests as "submitted" after a push. To determine which review requests should
be closed, it scans through each commit's commit message for the following
strings (case-insensitive): "Reviewed at <reviewboard_url>/r/<id>" or "Review
request #<id>".

This is what the JSON payload looks like:
http://code.google.com/p/support/wiki/PostCommitWebHooks

Testing Done:
All tests performed using an SVN and Mercurial repositories.

1) Push with the review request id in the commit message. Review request
   closed.
2) Push without a review request id in the commit message. (Error: Review
   request does not exist)
3) Push with non existent review request id. (Error: Review request does not
   exist)
4) Push with review id in the message that is already submitted. (logged a
   warning: request id already submitted.)
5) Push with review id in the message that has been marked as discarded.
   (review request marked as submitted.)

Reviewed at https://reviews.reviewboard.org/r/5744/
Fix permission name for creating repositories.

The Repository API already had some plumbing to allow users with a given
permission to create repositories regardless of their admin/staff status, but
it was using the wrong permission name. Trivial change.

Testing done: Ran unit tests.

Fixes bug 3307.
Merge branch 'release-1.7.x' into release-2.0.x
Merge branch 'release-2.0.x'