Redfish power operation

Added:
    - Resource variables paths.
    - Keyword to accept valid boot options.

Change-Id: Id49db5c351520116475971cda40c3d5ee32ed20d
Signed-off-by: Sridevi Ramesh <sridevra@in.ibm.com>
diff --git a/data/variables.py b/data/variables.py
index 642dc13..872c4e9 100755
--- a/data/variables.py
+++ b/data/variables.py
@@ -148,7 +148,8 @@
 
 # Boot options and URI variables.
 POWER_ON = 'On'
-POWER_GRACEFULL_OFF = "GracefulShutdown"
+POWER_GRACEFUL_OFF = "GracefulShutdown"
+POWER_GRACEFUL_RESTART = "GracefulRestart"
 POWER_FORCE_OFF = 'ForceOff'
 
 REDFISH_POWER_URI = 'Systems/1/Actions/ComputerSystem.Reset'