Remove unused parameter

Also update a few null pointers in this function to be consistent with
new null pointers being added.

Patch by Robert Matusewicz!

Differential Revision: http://reviews.llvm.org/D3123

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205682 91177308-0d34-0410-b5e6-96231b3b80d8