Terminate grpc process when olt is deleted

Change-Id: Ic6703719fb1eeb4e06e37dc7e08073b40b352e57
diff --git a/voltha/adapters/openolt/grpc/logconfig.yml b/voltha/adapters/openolt/grpc/logconfig.yml
index 70ee670..8ff722b 100644
--- a/voltha/adapters/openolt/grpc/logconfig.yml
+++ b/voltha/adapters/openolt/grpc/logconfig.yml
@@ -30,7 +30,7 @@
     stream: ext://sys.stdout
   localRotatingFile:
     class: logging.handlers.RotatingFileHandler
-    filename: /var/log/openolt_grpc.log
+    filename: openolt_grpc.log
     formatter: default
     maxBytes: 2097152
     backupCount: 10
diff --git a/voltha/adapters/openolt/openolt_device.py b/voltha/adapters/openolt/openolt_device.py
index 9bcb6f3..52cecb4 100644
--- a/voltha/adapters/openolt/openolt_device.py
+++ b/voltha/adapters/openolt/openolt_device.py
@@ -379,6 +379,9 @@
     def delete(self):
         self.log.info('deleting-olt')
 
+        # Terminate the grpc subprocess
+        self._grpc.terminate()
+
         # Clears up the data from the resource manager KV store
         # for the device
         del self.resource_mgr