removes uniqnes check on slug when saving dashboards

pkg/api/dashboard.go

@@ -214,7 +214,7 @@ func PostDashboard(c *middleware.Context, cmd m.SaveDashboardCommand) Response {
 	}
 
 	if err != nil {
-		if err == m.ErrDashboardWithSameNameExists {
+		if err == m.ErrDashboardWithSameUIDExists {
 			return Json(412, util.DynMap{"status": "name-exists", "message": err.Error()})
 		}
 		if err == m.ErrDashboardVersionMismatch {