use correct AS400 reflector when dbms_name/_ver is none

Fixes #182

Signed-off-by: Michael Maltese <michaeljosephmaltese@gmail.com>

Author: ligfx

ibm_db_sa/base.py

@@ -790,13 +790,13 @@ def initialize(self, connection):
         DB2Dialect.serverType = self.dbms_name
         super(DB2Dialect, self).initialize(connection)
         # check server type logic here
-        _reflector_cls = ibm_reflection.DB2Reflector
+        _reflector_cls = self._reflector_cls
         if self.dbms_name == 'AS':
             _reflector_cls = ibm_reflection.AS400Reflector
         elif self.dbms_name == "DB2":
             _reflector_cls = ibm_reflection.OS390Reflector
         elif(self.dbms_name is None):
-            _reflector_cls = ibm_reflection.DB2Reflector
+            pass
         elif "DB2/" in self.dbms_name:
             _reflector_cls = ibm_reflection.DB2Reflector
         elif "IDS/" in self.dbms_name: