Added start_onos_cli function description with details about newly added
karafTimeout optional argument.
diff --git a/TestON/drivers/common/cli/onosclidriver.py b/TestON/drivers/common/cli/onosclidriver.py
index ded9602..7e6f142 100644
--- a/TestON/drivers/common/cli/onosclidriver.py
+++ b/TestON/drivers/common/cli/onosclidriver.py
@@ -173,6 +173,11 @@
             main.exit()
         
     def start_onos_cli(self, ONOS_ip, karafTimeout=""):
+    '''
+    karafTimeout is an optional arugument. karafTimeout value passed by user would be used to set the 
+    current karaf shell idle timeout. Note that when ever this property is modified the shell will exit and
+    the subsequent login would reflect new idle timeout.
+    '''
         try:
             self.handle.sendline("")
             x = self.handle.expect([