adding return None to _handle_integer when Service gives None or Null value

Author: adev-code

botocore/parsers.py

@@ -1331,7 +1331,10 @@ def _handle_boolean(self, shape, value):
         return ensure_boolean(value)
 
     def _handle_integer(self, shape, value):
-        return int(value)
+        if value is None:
+            return None
+        else:
+            return int(value)
 
     def _handle_float(self, shape, value):
         return float(value)