Partially revert r191192: Fix -Wunused-variable error when assertions are disabled and -Werror is in use.

An unrelated change crept in because 'svn revert' isn't recursive by default.
The unrelated changes have been reverted.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191193 91177308-0d34-0410-b5e6-96231b3b80d8