[VOL-4237] Keep log files unless  is set to false

Change-Id: I2d11554b49c12d13c354f0c5f883962e4d8f10bc
diff --git a/tests/functional/Voltha_MultiOLT_Tests.robot b/tests/functional/Voltha_MultiOLT_Tests.robot
index bfff1d3..c955ff8 100755
--- a/tests/functional/Voltha_MultiOLT_Tests.robot
+++ b/tests/functional/Voltha_MultiOLT_Tests.robot
@@ -55,6 +55,10 @@
 # Per-test logging on failure is turned off by default; set this variable to enable
 ${container_log_dir}    ${None}
 
+# logging flag to enable Collect Logs, can be passed via the command line too
+# example: -v logging:False
+${logging}    True
+
 *** Test Cases ***
 Verify OLT after rebooting physically - MultipleOLT
     [Documentation]    Test the physical reboot of the OLT