BMC: Update u-boot environment variables.

- Create a service file that can update the u-boot variables
  (kernelname, root and ubiblock) to point to a different
  BMC version.
- This service file will be called by the BMC ItemUpdater
  if a user sets BMC version priority to the lowest value.

Change-Id: Ic83c7e7a1c36eefc6c0b1b12b2077f5a866db36c
Signed-off-by: Saqib Khan <khansa@us.ibm.com>
diff --git a/common/recipes-phosphor/flash/phosphor-software-manager/obmc-flash-bmc b/common/recipes-phosphor/flash/phosphor-software-manager/obmc-flash-bmc
index ddc0491..6725eaa 100644
--- a/common/recipes-phosphor/flash/phosphor-software-manager/obmc-flash-bmc
+++ b/common/recipes-phosphor/flash/phosphor-software-manager/obmc-flash-bmc
@@ -327,10 +327,10 @@
   ubiremount)
     remount_ubi
     ;;
-  preupdate)
+  createenvbackup)
     backup_env_vars
     ;;
-  postupdate)
+  updateubootvars)
     version="$2"
     update_env_vars
     ;;