MT#63171 refcount registerApplication

Apps registered through registerFactory4App or registerApplication get
put into the same name2app map as apps registered from loadAppPlugIn.
For consistent references, refcount these as well.

Change-Id: I9b616257555533a8ea5847a95b4fa5c0f2e91877

core/AmPlugIn.cpp

@@ -782,6 +782,7 @@ bool AmPlugIn::registerFactory4App(const string& app_name, AmSessionFactory* f)
 	 app_name.c_str());
     res =  false;
   } else {
+    inc_ref(f);
     name2app.insert(make_pair(app_name,f));
     res = true;
   }