1. Update the logic of UpdateVariable() for updating variable from:

1. Update the logic of UpdateVariable() for updating variable from:
set old variable to IN_DELETED_TRANSITION -> check if reclaim is needed(If yes, do reclaim) -> add new variable -> set old variable to DELETED if no reclaim happened.
to:
set old variable to IN_DELETED_TRANSITION -> check if reclaim is needed(If yes, do reclaim) -> add new variable -> set old variable to DELETED.
2. Update UpdateVariable() to correctly handle the case "both ADDED and IN_DELETED_TRANSITION variable are present", and delete both old ADDED and IN_DELETED_TRANSITION variable when deleting or updating variable.
3. Update VariableServiceGetNextVariableName() to return the valid IN_DELETED_TRANSITION variable if only IN_DELETED_TRANSITION variable is present.

Signed-off-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Ruiyu Ni <ruiyu.ni@intel.com>
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@14065 6f19259b-4bc3-4df7-8a09-765794883524