Merge branch 'jk/remote-tracking-ref-leakfix' into hn/status-compare-with-push

* jk/remote-tracking-ref-leakfix: remote: always allocate branch.push_tracking_ref remote: fix leak in branch_get_push_1() with invalid "simple" config remote: drop const return of tracking_for_push_dest() remote: return non-const pointer from error_buf()