AddonManager: Check that the addon folder actually contains files before declaring it installed
AddonManager: Check that the addon folder actually contains files before declaring it installed

Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master