VOL-4618: If power_switch_port config is missing skip reboot procedure
on the ONU.
Also add Zyxel ONU back to rlt-1600x OLT on master.

Change-Id: Iec49f1cf856bc017cb6988329bad0643162de39a
diff --git a/tests/tt-workflow/Voltha_TT_FailureScenarios.robot b/tests/tt-workflow/Voltha_TT_FailureScenarios.robot
index dc3ac9e..6895aeb 100755
--- a/tests/tt-workflow/Voltha_TT_FailureScenarios.robot
+++ b/tests/tt-workflow/Voltha_TT_FailureScenarios.robot
@@ -96,6 +96,8 @@
         ${onu_device_id}=    Get Device ID From SN    ${src['onu']}
         ${onu_port}=    Wait Until Keyword Succeeds    ${timeout}    2s
         ...    Get ONU Port in ONOS    ${src['onu']}    ${of_id}
+        # If the power switch port is not specified, continue
+        Continue For Loop If    '${src["power_switch_port"]}' == '${None}'
         # Disable Power Switch
         Disable Switch Outlet    ${src['power_switch_port']}
         # TODO: Add verification for MCAST
diff --git a/tests/tt-workflow/Voltha_TT_PODTests.robot b/tests/tt-workflow/Voltha_TT_PODTests.robot
index dcf29fa..f5caa13 100755
--- a/tests/tt-workflow/Voltha_TT_PODTests.robot
+++ b/tests/tt-workflow/Voltha_TT_PODTests.robot
@@ -83,6 +83,8 @@
     FOR    ${I}    IN RANGE    0    ${num_all_onus}
         ${src}=    Set Variable    ${hosts.src[${I}]}
         ${dst}=    Set Variable    ${hosts.dst[${I}]}
+        # If the power switch port is not specified, continue
+        Continue For Loop If    '${src["power_switch_port"]}' == '${None}'
         Disable Switch Outlet    ${src['power_switch_port']}
         Sleep    10s
         Enable Switch Outlet    ${src['power_switch_port']}