Passing NULL is non-sensical. The error message leaves to be desired,
though, as it leaks internal implementation details. Catch it at the
`git_config_set_string` level and set an appropriate error message.
- Fix stack corruption introduced in 9bccf33c due to passing pointer to
local variable _cred_acquire_called.
- Fix strcmp in do_verify_push_status when expected or actual push_status
is NULL
For clone to work as expected, it should be using a SAFE_CREATE
checkout (i.e. create files that are missing, even if the target
tree matches the current HEAD).
* gen_pktline() in smart_protocol.c was skipping refspecs that deleted
refs that were not advertised by the server. The new behavior is to
send a delete command with an old-id of zero, which matches the behavior
of the official git client.
* Update test_network_push__delete() in reaction to above fix.
* Obviate messy logic that handles missing push_spec rrefs by canonicalizing
push_spec. After calculate_work(), loid, roid, and rref, are filled in with
exactly what is sent to the server
