Replace swsssdk.SonicV2Connector with swsscommon.SonicV2Connector (SWIG wrapper of C++ implementation) in production code (sonic-net#162)

This is the following step for merging sonic-py-swsssdk into sonic-swss-common sonic-net/sonic-swss-common#387

Note: Test code could still using old python implementation

Author: qiluo-msft

src/sonic_ax_impl/mibs/__init__.py

@@ -2,7 +2,7 @@
 import re
 import os
 
-from swsssdk import SonicV2Connector
+from swsscommon.swsscommon import SonicV2Connector
 from swsssdk import SonicDBConfig
 from swsssdk import port_util
 from swsssdk.port_util import get_index_from_str

tests/mock_tables/dbconnector.py

@@ -4,9 +4,12 @@
 import sys
 
 import mockredis
-from swsssdk.interface import redis, DBInterface
+import redis
+import swsssdk
 from swsssdk import SonicV2Connector
 from swsssdk import SonicDBConfig
+from swsssdk.interface import DBInterface
+from swsscommon import swsscommon
 
 
 if sys.version_info >= (3, 0):
@@ -91,7 +94,7 @@ def __init__(self, *args, **kwargs):
         # to identify the file path to load the db json files.
         namespace = kwargs.pop('namespace')
         db_name = kwargs.pop('db_name')
-        self.decode_responses = kwargs.pop('decode_responses') == True
+        self.decode_responses = kwargs.pop('decode_responses', False) == True
         fname = db_name.lower() + ".json"
         self.pubsub = MockPubSub()
 
@@ -143,3 +146,9 @@ def keys(self, pattern='*'):
 mockredis.MockRedis.config_set = config_set
 redis.StrictRedis = SwssSyncClient
 SonicV2Connector.connect = connect_SonicV2Connector
+swsscommon.SonicV2Connector = SonicV2Connector
+
+# pytest case collecting will import some module before monkey patch, so reload
+from importlib import reload
+import sonic_ax_impl.mibs
+reload(sonic_ax_impl.mibs)