Update Reboot marker for journald persistency check

Changes:
    - Before "-- Reboot --"    after
      Example:
      "-- Boot 88811756bcbe44bc823cc20751147b3c --"

Change-Id: I86ab5c0ea287c8a47e8d6fe30e71302b32510d8f
Signed-off-by: George Keishing <gkeishin@in.ibm.com>
diff --git a/redfish/managers/test_managers_bmc.robot b/redfish/managers/test_managers_bmc.robot
index fd23064..1336062 100644
--- a/redfish/managers/test_managers_bmc.robot
+++ b/redfish/managers/test_managers_bmc.robot
@@ -18,7 +18,7 @@
 ${SYSTEM_SHUTDOWN_TIME}    ${5}
 
 # Strings to check from journald.
-${REBOOT_REGEX}    ^\-- Reboot --
+${REBOOT_REGEX}    ^\-- Boot
 
 *** Test Cases ***