Close ONOS cli log handles on cli disconnect.
And truncate the onoscli.session file instead of appending to cli session log file on every connect.

Change-Id: I3bdacb5aabd2e708cc8a86d8076a17e2f1bb9077
diff --git a/src/test/cli/onosclidriver.py b/src/test/cli/onosclidriver.py
index ca43f7a..4ea1fb6 100644
--- a/src/test/cli/onosclidriver.py
+++ b/src/test/cli/onosclidriver.py
@@ -140,6 +140,7 @@
                     self.handle.expect( "\$" )
                     self.handle.sendline( "exit" )
                     self.handle.expect( "closed" )
+                self.close_log_handles()
         except TypeError:
             main.log.exception( self.name + ": Object not as expected" )
             response = main.FALSE
@@ -4689,4 +4690,3 @@
   flows_json = onos_cli.flows(state = "ADDED")
   print('Flows %s' %flows_json)
   onos_cli.disconnect()
-