Bug 2246 fixed

Change-Id: Ic35d131d4e44686de207b0a6acc3360e04306cb2
Signed-off-by: Pedro Escaleira <escaleira@av.it.pt>
diff --git a/osm_common/dbmongo.py b/osm_common/dbmongo.py
index c9b384b..e5e12c6 100644
--- a/osm_common/dbmongo.py
+++ b/osm_common/dbmongo.py
@@ -284,7 +284,7 @@
             with self.lock:
                 collection = self.db[table]
                 db_filter = self._format_filter(q_filter)
-                count = collection.count(db_filter)
+                count = collection.count_documents(db_filter)
             return count
         except DbException:
             raise