Fix move-of-const in ThreadWheelTimekeeper

Summary: [Folly] Fix move-of-const in `ThreadWheelTimekeeper`.

Reviewed By: capickett

Differential Revision: D9950653

fbshipit-source-id: 76d45cdac1026c41de73489936c4afdac3f57fd7

folly/futures/ThreadWheelTimekeeper.cpp

@@ -81,7 +81,8 @@ struct WTCallback : public std::enable_shared_from_this<WTCallback>,
     // This is not racing with timeoutExpired anymore because this is called
     // through Future, which means Core is still alive and keeping a ref count
     // on us, so what timeouExpired is doing won't make the object go away
-    base_->runInEventBaseThread([me = shared_from_this(), ew = std::move(ew)] {
+    base_->runInEventBaseThread(
+        [me = shared_from_this(), ew = std::move(ew)]() mutable {
           me->cancelTimeout();
           // Don't need Promise anymore, break the circular reference
           auto promise = me->stealPromise();