Handle duplicated locks in Acquires class constructor.

ccserver/utils.py

@@ -27,7 +27,7 @@ class Acquires(object):
     '''
 
     def __init__(self, *locks):
-        self._locks = sorted(locks, key=lambda x: id(x))
+        self._locks = sorted(set(locks), key=lambda x: id(x))
 
     def __enter__(self):
         for lock in self._locks: