localrepo: ensure files unicity in commit() (issue 714)

mercurial/localrepo.py

@@ -661,6 +661,8 b' class localrepository(repo.repository):'
                match=util.always, force=False, force_editor=False,
                p1=None, p2=None, extra={}, empty_ok=False):
         wlock = lock = tr = None
+        if files:
+            files = util.unique(files)
         try:
             commit = []
             remove = []