Remove redundant comma around parenthesis in parameter list.

Reviewers: djasper

Subscribers: cfe-commits, klimek

Differential Revision: https://reviews.llvm.org/D24501

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@281344 91177308-0d34-0410-b5e6-96231b3b80d8