Change project.revision to revisionExpr and revisionId

The revisionExpr field now holds an expression from the manifest,
such as "refs/heads/master", while revisionId holds the current
commit-ish SHA-1 of the revisionExpr.  Currently that is only
filled in if the manifest points directly to a SHA-1.

Signed-off-by: Shawn O. Pearce <sop@google.com>
5 files changed