Add rotating log file inside the relevant docker containers

Change-Id: I021c0e3489a823d6b67178247db73c0f24c36181
diff --git a/ofagent/ofagent.yml b/ofagent/ofagent.yml
index 2b1d69e..1c8e764 100644
--- a/ofagent/ofagent.yml
+++ b/ofagent/ofagent.yml
@@ -27,6 +27,13 @@
             tag: voltha.logging
             formatter: fluent_fmt
             level: DEBUG
+        localRotatingFile:
+            class: logging.handlers.RotatingFileHandler
+            filename: ofagent.log
+            formatter: default
+            maxBytes: 2097152
+            backupCount: 10
+            level: DEBUG
         null:
             class: logging.NullHandler
 
@@ -38,7 +45,7 @@
             handlers: [null]
             propagate: False
         '': # root logger
-            handlers: [console, fluent]
+            handlers: [console, fluent, localRotatingFile]
             level: INFO # this can be bumped up/down by -q and -v command line
                         # options
             propagate: False