Properly fix unused variable in disable-assert builds.

I missed the side-effects of ParseBFI in my previous attempt (r252748).
Thanks dblaikie for the suggestion of adding a void use of the unused
variable instead.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252751 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed