sync: Update default -j flag from manifest

If the manifest is updated and the default sync-j attribute
was modified, honor it during this sync session if the user
has not supplied a -j flag on the command line.

Change-Id: I127ee5c779e2bbbb40b30bddc10ec1fa704b3bf3
Signed-off-by: Shawn O. Pearce <sop@google.com>
1 file changed