Use the API EfiBootManagerDeleteLoadOptionVariable in UefiBootManagerLib to replace the same logic in function Var_DelBootOption/Var_DelDriverOption. This can make code clean and prevent potential bugs. https://bugzilla.tianocore.org/show_bug.cgi?id=391 Cc: Eric Dong <eric.dong@intel.com> Cc: Ruiyu Ni <ruiyu.ni@intel.com> Cc: Star Zeng <star.zeng@intel.com> Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Dandan Bi <dandan.bi@intel.com> Reviewed-by: Ruiyu Ni <ruiyu.ni@intel.com> Reviewed-by: Eric Dong <eric.dong@intel.com>