Fix for ONU Physical Reboot

Change-Id: I7c66204cd799a249eb3ccb253c2045c5bd321174
diff --git a/tests/dt-workflow/Voltha_DT_FailureScenarios.robot b/tests/dt-workflow/Voltha_DT_FailureScenarios.robot
index 67d5cce..2fa6030 100644
--- a/tests/dt-workflow/Voltha_DT_FailureScenarios.robot
+++ b/tests/dt-workflow/Voltha_DT_FailureScenarios.robot
@@ -75,6 +75,7 @@
     FOR    ${I}    IN RANGE    0    ${num_onus}
         ${src}=    Set Variable    ${hosts.src[${I}]}
         ${dst}=    Set Variable    ${hosts.dst[${I}]}
+        ${onu_device_id}=    Get Device ID From SN    ${src['onu']}
         ${onu_port}=    Run Keyword And Continue On Failure    Wait Until Keyword Succeeds    ${timeout}    2s
         ...    Get ONU Port in ONOS    ${src['onu']}    ${of_id}
         # Disable Power Switch
@@ -91,7 +92,6 @@
         Sleep    5s
         # Enable Power Switch
         Enable Switch Outlet    ${src['power_switch_port']}
-        ${onu_device_id}=    Get Device ID From SN    ${src['onu']}
         # Check ONU port is Enabled in ONOS
         Run Keyword And Continue On Failure    Wait Until Keyword Succeeds   120s   2s
         ...    Verify ONU Port Is Enabled   ${ONOS_SSH_IP}    ${ONOS_SSH_PORT}    ${onu_port}