Drop workaround for python-bynary-memcached < 0.23

This removes the workaround for a very old bug, which was fixed in 0.23 (released in 2014).

Closes: #253
Pull-request: #253
Pull-request-sha: a25018c

Change-Id: I93e8a11765a1e2f2a41811f41ba8f2ca4da58694

Author: kajinamit

dogpile/cache/backends/memcached.py

@@ -408,25 +408,8 @@ def _imports(self):
         global bmemcached
         import bmemcached
 
-        class RepairBMemcachedAPI(bmemcached.Client):
-            """Repairs BMemcached's non-standard method
-            signatures, which was fixed in BMemcached
-            ef206ed4473fec3b639e.
-
-            """
-
-            def add(self, key, value, timeout=0):
-                try:
-                    return super(RepairBMemcachedAPI, self).add(
-                        key, value, timeout
-                    )
-                except ValueError:
-                    return False
-
-        self.Client = RepairBMemcachedAPI
-
     def _create_client(self):
-        return self.Client(
+        return bmemcached.Client(
             self.url,
             username=self.username,
             password=self.password,