load_minigraph: restart hostcfgd (sonic-net#511)

* In sync with our latest change, where we default failthrough to be False.
Reference: Pull request sonic-net#2746

* Loading minigraph, flushes DB, which is not sent as updates to hostcfgd. So stop hostcfgd before load and restart after load, to be able to act in sync with updated CONFIG-DB.

config/main.py

@@ -294,6 +294,7 @@ def _stop_services():
         'pmon',
         'bgp',
         'teamd',
+        'hostcfgd',
     ]
     for service in services:
         try:
@@ -315,6 +316,7 @@ def _restart_services():
         'lldp',
         'snmp',
         'dhcp_relay',
+        'hostcfgd',
     ]
     for service in services:
         try: