Fixed bug: using equals operator instead of assignment

Libs/PluginFramework/ctkServices.cpp

@@ -411,7 +411,7 @@ QList<ctkServiceRegistration*> ctkServices::getRegisteredByPlugin(ctkPluginPriva
   for (QHashIterator<ctkServiceRegistration*, QStringList> i(services); i.hasNext(); )
   {
     ctkServiceRegistration* sr = i.next().key();
-    if ((sr->d_func()->plugin = p))
+    if ((sr->d_func()->plugin == p))
     {
       res.push_back(sr);
     }