Commit ID is not included in review request if --include is used on rbt post.

Previously when --include was used on an rbt post, it would take the commit ID
of the current commit. The issue is that if someone uploaded multiple files
from the same commit separately, the identical commit IDs would cause conflicts
in the ReviewRequests. The solution is to not include the commit ID when
"--include" is used on an rbt post.

Testing Done:
Made a commit with two files in the change. I was able to post and publish both
without error, which would not happen normally. When looking on the review
board web ui, there was no commit id associated with either.

Bugs closed: 3328

Reviewed at https://reviews.reviewboard.org/r/5818/
Make 'rbt status' work better with public local sites.

With public local sites, it's possible that the 'user' link in the session
resource will be broken. This is because the users resource only includes users
who are part of the given local site.

This change makes 'rbt status' work a little better in this case. We don't
actually need any data from the user resource, since all we're looking up here
is the username. In this case, we can just use the title attribute of the link,
which also happens to save us an API request.

Testing done:
* Verified that 'rbt status' still works.
* Ran unit tests.

Fixes bug 3350.

Reviewed at https://reviews.reviewboard.org/r/5863/