Avoid warning on empty expressions

For some reason, Q_UNUSED includes already a semicolon, adding one
on the user side creates an additional empty statement.

Change-Id: I9c5e8fac381345a60792cb75e2938fd53958d3b0
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/cmakeprojectmanager/servermode.cpp

@@ -453,7 +453,7 @@ void ServerMode::parseJson(const QVariantMap &data)
 
 void ServerMode::handleHello(const QVariantMap &data)
 {
-    Q_UNUSED(data);
+    Q_UNUSED(data)
     QVariantMap extra;
     QVariantMap version;
     version.insert("major", m_majorProtocol);