Tell gitfs to ref the remote refs in the repo fetch
Tell gitfs to ref the remote refs in the repo fetch

This lowers overhead and fixes the updae bug, it also fixes
Fix #3315
Fix #3316
As for #3316, use salt-run fileserver.update to explicitly update
instead of waiting for the built in check, checking with every file
lookup would cause far too many calls to the remote git server

saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt