deref_tag() prints a warning if the object that a tag refers to does not
exist. However, when a partial clone has an annotated tag from its
promisor remote, but not the object that it refers to, printing a
warning on such a tag is incorrect.
This occurs, for example, when the checkout that happens after a partial
clone causes some objects to be fetched - and as part of the fetch, all
local refs are read. The test included in this patch demonstrates this
situation.
Therefore, do not print a warning in this case.
Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>