Historically, we've provided support for specifying a Review Board

server URL as a Perforce counter key/value, useful for very large

deployments that don't want to juggle .reviewboardrc files. This has

still left RBTools to scan for repositories, comparing paths, which is

slow.
This change introduces some base level support for SCMClients to

provide a repository name as part of the RepositoryInfo, which will be

used as a fallback if an explicit repository name is not specified

during repository and review request lookup.
For the Perforce side, a new reviewboard.repository_name counter is

now supported, which provides the value for this new field.
While we still recommend a .reviewboardrc for deployments, this should

help RBTools work faster and more reliably with very large, old,

established Perforce repositories.

Unit tests pass.
Set the counter in a test repository and verified Review Board was trying

to use it for posting changes and displaying status.