Upgrade to oauth2client 2.0.1. Remove support for seperate pem keys.

src/oauth2client/file.py

@@ -36,29 +36,14 @@ class Storage(BaseStorage):
     """Store and retrieve a single credential to and from a file."""
 
     def __init__(self, filename):
+        super(Storage, self).__init__(lock=threading.Lock())
         self._filename = filename
-        self._lock = threading.Lock()
 
     def _validate_file(self):
         if os.path.islink(self._filename):
             raise CredentialsFileSymbolicLinkError(
                 'File: %s is a symbolic link.' % self._filename)
 
-    def acquire_lock(self):
-        """Acquires any lock necessary to access this Storage.
-
-        This lock is not reentrant.
-        """
-        self._lock.acquire()
-
-    def release_lock(self):
-        """Release the Storage lock.
-
-        Trying to release a lock that isn't held will result in a
-        RuntimeError.
-        """
-        self._lock.release()
-
     def locked_get(self):
         """Retrieve Credential from file.