Bump up log level

Summary: This log was getting annoying in tests, bump up the logging level

Test Plan: contbuild

Reviewed By: afrind@fb.com

Subscribers: trunkagent, doug, fugalh, njormrod, folly-diffs@

FB internal diff: D1710608

Signature: t1:1710608:1417468546:770dfb7201ff6477b349c01e638f704a2ef1b7ce

folly/experimental/wangle/acceptor/Acceptor.cpp

@@ -420,7 +420,7 @@ Acceptor::forceStop() {
 void
 Acceptor::dropAllConnections() {
   if (downstreamConnectionManager_) {
-    LOG(INFO) << "Dropping all connections from Acceptor=" << this <<
+    VLOG(3) << "Dropping all connections from Acceptor=" << this <<
       " in thread " << base_;
     assert(base_->isInEventBaseThread());
     forceShutdownInProgress_ = true;