Search username cache before database by name

If the input string conforms to our username pattern, search the
username cache as it will be quicker than looking at the database
for a full name substring, and probably is going to match an account,
especially in small group settings where people know each other's
local usernames.

Change-Id: I827f59d9c0fc9ce5b515b9611561d718733036d2
Signed-off-by: Shawn O. Pearce <sop@google.com>
1 file changed