Notify from the main curl worker loop

After the notification is done, the request may be deleted by the
owning S3File instance.  Do not call `Notify` from within the curl
result processing function as the request object needs to be alive
to release the curl handle.

src/CurlUtil.cc

@@ -315,6 +315,7 @@ void CurlWorker::Run() {
 							 "Processing result from curl");
 				op->ProcessCurlResult(iter->first, res);
 				op->ReleaseHandle(iter->first);
+				op->Notify();
 				running_handles -= 1;
 				curl_multi_remove_handle(multi_handle, iter->first);
 				if (res == CURLE_OK) {

src/HTTPCommands.cc

@@ -639,9 +639,6 @@ void HTTPRequest::Notify() {
 HTTPRequest::CurlResult HTTPRequest::ProcessCurlResult(CURL *curl,
 													   CURLcode rv) {
 
-	auto cleaner = [&](void *) { Notify(); };
-	auto unique = std::unique_ptr<void, decltype(cleaner)>((void *)1, cleaner);
-
 	if (rv != 0) {
 		if (errorCode.empty()) {
 			errorCode = "E_CURL_IO";