Diffusion rejects notes associated with commits. Pushing notes fails with the following error message:
```
remote: [2015-09-10 11:49:10] EXCEPTION: (Exception) Unable to identify the reftype of 'refs/notes/commits'. Rejecting push. at [<phabricator>/src/applications/diffusion/engine/DiffusionCommitHookEngine.php:414]
remote: arcanist(head=master, ref.master=a5304e472d18), phabricator(head=exper, ref.master=ce7c2097b216, ref.exper=185f42081cfe), phutil(head=master, ref.master=dc0626970a6d)
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]
To ssh://vcs@domain/diffusion/SANDBOX/sandbox.git
! [remote rejected] refs/notes/commits -> refs/notes/commits (pre-receive hook declined)
error: failed to push some refs to 'ssh://vcs@domain/diffusion/SANDBOX/sandbox.git'
```
To reproduce:
```
git commit --allow-empty -m "Hello"
git notes add -m "Some note"
git push origin refs/notes/commits
```