sceneconverter: reorder all plugin managers to be in a single place.

src/Magnum/SceneTools/sceneconverter.cpp

@@ -334,10 +334,16 @@ is specified as well, the IDs reference attributes of the first mesh.)")
             Warning{} << "Ignoring output file for --info:" << args.value<Containers::StringView>("output");
     }
 
+    /* Importer manager */
     PluginManager::Manager<Trade::AbstractImporter> importerManager{
         args.value("plugin-dir").empty() ? Containers::String{} :
         Utility::Path::join(args.value("plugin-dir"), Trade::AbstractImporter::pluginSearchPaths().back())};
 
+    /* Scene converter manager */
+    PluginManager::Manager<Trade::AbstractSceneConverter> converterManager{
+        args.value("plugin-dir").empty() ? Containers::String{} :
+        Utility::Path::join(args.value("plugin-dir"), Trade::AbstractSceneConverter::pluginSearchPaths().back())};
+
     Containers::Pointer<Trade::AbstractImporter> importer = importerManager.loadAndInstantiate(args.value("importer"));
     if(!importer) {
         Debug{} << "Available importer plugins:" << ", "_s.join(importerManager.aliasList());
@@ -1409,10 +1415,6 @@ is specified as well, the IDs reference attributes of the first mesh.)")
             Debug{} << "Fuzzy duplicate removal:" << beforeVertexCount << "->" << mesh->vertexCount() << "vertices";
     }
 
-    PluginManager::Manager<Trade::AbstractSceneConverter> converterManager{
-        args.value("plugin-dir").empty() ? Containers::String{} :
-        Utility::Path::join(args.value("plugin-dir"), Trade::AbstractSceneConverter::pluginSearchPaths().back())};
-
     /* Assume there's always one passed --converter option less, and the last
        is implicitly AnySceneConverter. All converters except the last one are
        expected to support ConvertMesh and the mesh is "piped" from one to the