I tried to push to an existing repository, which I previously filled with `git push origin --all` (cf. T8874). Phabricator replied with `Unable to identify the reftype of 'refs/remotes/origin/master'. Rejecting push.`.
```
$ git push origin --mirror
Counting objects: 313, done.
Delta compression using up to 4 threads.
Compressing objects: 100% (213/213), done.
Writing objects: 100% (286/286), 146.11 KiB | 0 bytes/s, done.
Total 286 (delta 71), reused 283 (delta 69)
remote: [2015-07-23 12:14:17] EXCEPTION: (Exception) Unable to identify the reftype of 'refs/remotes/origin/master'. Rejecting push. at [<phabricator>/src/applications/diffusion/engine/DiffusionCommitHookEngine.php:412]
remote: arcanist(head=stable, ref.master=999eb9376568, ref.stable=d54cb072facd), libphremoteuser(head=master, ref.master=1def4e2d7f07), phabricator(head=stable, ref.master=f0bf7a8e2621, ref.stable=2e82fb07cdc1), phutil(head=stable, ref.master=aa6cd8f7e5e5, ref.stable=83f09
f6c5a03), sprint(head=production, ref.master=4912ecf41ef1, ref.production=2846fc28ae19)
remote: #0 DiffusionCommitHookEngine::findGitRefUpdates() called at [<phabricator>/src/applications/diffusion/engine/DiffusionCommitHookEngine.php:220]
remote: #1 DiffusionCommitHookEngine::findRefUpdates() called at [<phabricator>/src/applications/diffusion/engine/DiffusionCommitHookEngine.php:124]
remote: #2 DiffusionCommitHookEngine::execute() called at [<phabricator>/scripts/repository/commit_hook.php:133]
```