Since 612300b3

 (Show a warning if .SRCINFO is unchanged, 2015-09-29), the
git-update script displays a warning when a ref update does not affect
the content of the package base meta data. We also invoke git-update to
rebuild the package base details in the aurweb database when a package
base is restored via the SSH interface. In that case, fake information
is passed to the update hook: Both the old and the new object IDs refer
to the current HEAD. Check for such "Everything up-to-date" updates and
not display the ".SRCINFO unchanged" in these cases.

Signed-off-by: Lukas Fleischer <lfleischer@archlinux.org>