[PATCH 2/5] refs.c: make add_packed_ref return an error instead of calling die

Change add_packed_ref to return an error instead of calling die(). Update all callers to check the return value of add_packed_ref. We can also skip checking the refname format since this function is now static and only called from the transaction code. If we are updating a ref and the refname is b

[PATCH 2/5] refs.c: make add_packed_ref return an error instead of calling die

Change add_packed_ref to return an error instead of calling die(). Update all callers to check the return value of add_packed_ref. We can also skip checking the refname format since this function is now static and only called from the transaction code. If we are updating a ref and the refname is b