Use a variable to appease a no-asserts bot, NFC

Failure URL:
http://lab.llvm.org:8011/builders/lld-x86_64-darwin13/builds/22836

llvm-svn: 335648

lib/Transforms/Utils/Local.cpp

@@ -1721,6 +1721,7 @@ void llvm::insertReplacementDbgValues(
       auto *I = DIB.insertDbgValueIntrinsic(&To, OldDII->getVariable(), Expr,
                                             OldDII->getDebugLoc().get(),
                                             &InsertBefore);
+      (void)I;
       LLVM_DEBUG(dbgs() << "REPLACE:  " << *I << '\n');
     }
 }