remote.c: remove BUG in show_push_unqualified_ref_name_error()

When "git push <remote> <src>:<dst>" does not spell out the destination side of the ref fully, and when <src> is not given as a reference but an object name, the code tries to give advice messages based on the type of that object. The type is determined by calling odb_read_object_info() and signalled by its return value. The code however reported a programming error with BUG() when this function said that there is no such object, which happens when the object name is given as a full hexadecimal (if the object name is given as a partial hexadecimal or an non-existing ref, the function would have died without returning, so this BUG() wouldn't have triggered). This is wrong. It is an ordinary end-user mistake to give an object name that does not exist and treated as such. An example of the error message produced is as follows: error: The destination you provided is not a full refname (i.e., starting with "refs/"). We tried to guess what you meant by: - Looking for a ref that matches 'branch' on the remote side. - Checking if the <src> being pushed ('0000000000000000000000000000000000000001') is a ref in "refs/{heads,tags}/". If so we add a corresponding refs/{heads,tags}/ prefix on the remote side. Neither worked, so we gave up. You must fully qualify the ref. BUG: remote.c:1221: '0000000000000000000000000000000000000001' should be commit/tag/tree/blob, is '-1' fatal: the remote end hung up unexpectedly Aborted (core dumped) Helped-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Denton Liu <liu.denton@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>