pull requests: use org_ref with correct symbolic name instead of fake one

So far this is only cosmetic, but it might make a difference for further
processing of a PR.

rhodecode/controllers/pullrequests.py

@@ -326,9 +326,9 b' class PullrequestsController(BaseRepoCon'
             return redirect(url('pullrequest_home', repo_name=repo_name))
 
         org_repo = _form['org_repo']
-        org_ref = 'rev:merge:%s' % _form['merge_rev']
+        org_ref = _form['org_ref'] # will end with merge_rev but have symbolic name
         other_repo = _form['other_repo']
-        other_ref = 'rev:ancestor:%s' % _form['ancestor_rev']
+        other_ref = 'rev:ancestor:%s' % _form['ancestor_rev'] # could be calculated from other_ref ...
         revisions = [x for x in reversed(_form['revisions'])]
         reviewers = _form['review_members']