ShellPkg: Fixed variable set but never used

This warning/error raised by ARM toolchain prevents to build
the EFI Shell for ARM 32-bit with this toolchain.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Olivier Martin <olivier.martin@arm.com>
Reviewed-by: Jaben Carsey <jaben.carsey@intel.com>



git-svn-id: svn://svn.code.sf.net/p/edk2/code/trunk/edk2/ShellPkg@16323 6f19259b-4bc3-4df7-8a09-765794883524