REST power on skip mode for callout test cases.

Changes:
    - Added stack_mode=skip for power on to reduce execution
      time taken for the test cases. Power on per test case
      is not required, however we need to re-poweron if it
      was off.

Change-Id: I554360ee5e9f31fb6506ab7412d4f991353fad54
Signed-off-by: George Keishing <gkeishin@in.ibm.com>
diff --git a/extended/test_association.robot b/extended/test_association.robot
index 64c47eb..db99e12 100755
--- a/extended/test_association.robot
+++ b/extended/test_association.robot
@@ -268,7 +268,7 @@
 Test Setup Execution
     [Documentation]  Do test case setup tasks.
 
-    REST Power On  quiet=1
+    REST Power On  stack_mode=skip  quiet=1
     ${status}=  Run Keyword And Return Status  Callout Test Binary Exist
     Run Keyword If  ${status} == ${False}  Install Tarball
     Delete All Error Logs