Currently when doing a sync against a revision locked manifest,
sync has no option but to fall back to sync'ing the entire refs space;
it doesn't know which ref to ask for that contains the sha1 it wants.
This sucks if we're in -c mode; thus when we generate a revision
locked manifest, record the originating branch- and try syncing that
branch first. If the sha1 is found within that branch, this saves
us having to pull down the rest of the repo- a potentially heavy
saving.
If that branch doesn't have the desired sha1, we fallback to sync'ing
everything.
Change-Id: I99a5e44fa1d792dfcada76956a2363187df94cf1
This can be useful to create a new manifest from an existing client,
especially if the client wants to use the "-r" option to set each
project's revision to the current commit SHA-1, making a sort of a
tag file that can be used to recreate this exact state elsewhere.
Signed-off-by: Shawn O. Pearce <sop@google.com>
