Free resources in the reverse order of allocation (#237)

When resources are freed in the reverse order as they are allocated,
it simplifies when you want to disable parts of the code when hunting for
memory leaks and undefined behavior.

app/dockerdwrapper.c

@@ -843,7 +843,8 @@ int main(int argc, char** argv) {
 
         stop_dockerd();
     }
-    main_loop_unref();
+
+    sd_disk_storage_free(sd_disk_storage);
 
     fcgi_stop();
 
@@ -858,9 +859,10 @@ int main(int argc, char** argv) {
         ax_parameter_free(app_state.param_handle);
     }
 
-    sd_disk_storage_free(sd_disk_storage);
     free(app_state.sd_card_area);
 
+    main_loop_unref();
+
     log_debug("Application exited with exit code %d", application_exit_code);
     return application_exit_code;
 }