Optimize checking vob UUIDs with several ClearCase repositories.
Optimize checking vob UUIDs with several ClearCase repositories.

When the server has several configured ClearCase repositories, we would make
HTTP calls for each one (using _get_repository_info()). This could potentially
add a lot of overhead.

This change builds an ordered list of ClearCase repositories, with the ones
that have a matching vobstag at the front. This list is then checked in order
to match the UUIDs, which makes it much faster.

This also has a fix for a side issue that I caught with restricted
repositories. In this case, the request would return with HTTP 403, which would
abort.

Testing Done:
- Posting reviews against authorized clearcase repo with matching vobstag still
  works.
- Posting reviews against authorized clearcase repo with no matching vobstag
  will work, even when there are some unauthorized clearcase repos in the
  list.
- Posting reviews against unauthorized clearcase repo returns an error.

Bugs closed: 3177

Reviewed at https://reviews.reviewboard.org/r/5166/

datjwu/rbtools,davidt/rbtools,1tush/rbtools,beol/rbtools,halvorlu/rbtools,halvorlu/rbtools,haosdent/rbtools,halvorlu/rbtools,reviewboard/rbtools,beol/rbtools,reviewboard/rbtools,davidt/rbtools,beol/rbtools,haosdent/rbtools,datjwu/rbtools,datjwu/rbtools,davidt/rbtools,haosdent/rbtools,reviewboard/rbtools