Fix `mongodb_user` compatibility with MongoDB 2.2 (used in Debian 7).

database/mongodb_user

@@ -81,13 +81,18 @@ author: Elliott Foster
 
 import ConfigParser
 try:
-    from pymongo import MongoClient
     from pymongo.errors import ConnectionFailure
     from pymongo.errors import OperationFailure
+    from pymongo import MongoClient
+except ImportError:
+    try:  # for older PyMongo 2.2
+        from pymongo import Connection as MongoClient
     except ImportError:
         pymongo_found = False
     else:
         pymongo_found = True
+else:
+    pymongo_found = True
 
 # =========================================
 # MongoDB module specific support methods.