Work around unused variable warning in release builds.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@189028 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Format/Format.cpp

@@ -439,6 +439,7 @@ private:
     for (std::deque<StateNode *>::iterator I = Path.begin(), E = Path.end();
          I != E; ++I) {
       unsigned Penalty = Indenter->addTokenToState(State, (*I)->NewLine, false);
+      (void)Penalty;
       DEBUG({
         if ((*I)->NewLine) {
           llvm::dbgs() << "Penalty for placing "