QtSupport: Fix leak of QtVersion

Change-Id: I70b45f7df322d4cf750664662a8d84946279192d
Reviewed-by: hjk <hjk@qt.io>

src/plugins/qtsupport/qtversionmanager.cpp

@@ -376,6 +376,7 @@ void QtVersionManagerImpl::updateFromInstaller(bool emitSignal)
                 qCDebug(log) << "  removing version" << qtVersion->detectionSource();
                 m_versions.remove(qtVersion->uniqueId());
                 removed << qtVersion->uniqueId();
+                delete qtVersion;
             }
         }
     }