We have two error messages that complain about the "sha1". Because we
are about to touch one of these sites and add some tests, let's first
modernize the messages to say "object ID" instead.
While at it, make the second one use `error()` instead of `warning()`.
After printing the message, we do not continue, but actually drop the
lock and return -1 without deleting the pseudoref.
Signed-off-by: Martin Ågren <martin.agren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>