Clean up default password from resource file

Changes:
     - Set the admin and service password to empty string

Tested:
     - Ran from Sandbox with the CLI inputs.

Change-Id: I775794dc7d00b047c5df28cde3c72f9090ebf0a8
Signed-off-by: George Keishing <gkeishin@in.ibm.com>
diff --git a/lib/resource.robot b/lib/resource.robot
index c85acee..711f8e5 100755
--- a/lib/resource.robot
+++ b/lib/resource.robot
@@ -31,8 +31,8 @@
 ${REST_USERNAME}       root
 ${REST_PASSWORD}       0penBmc
 ${OPENBMC_ADMIN_USERNAME}  admin
-${OPENBMC_ADMIN_PASSWORD}  0penBmc
-${SERVICE_USER_PASSWORD}   0penBmc
+${OPENBMC_ADMIN_PASSWORD}  ${EMPTY}
+${SERVICE_USER_PASSWORD}   ${EMPTY}
 
 # For users privilege admin or sudo.
 ${USER_TYPE}          ${EMPTY}