Bake-API: throws error if highpoly object(s) doesn't have uniform scale (fix T40156)

The real fix would be to support non-uniform scaled highpoly objects.
For more information see 8d29739

source/blender/editors/object/object_bake_api.c

@@ -508,13 +508,19 @@ static int bake(
 			if (ob_iter == ob_low)
 				continue;
 
+			if (ob_iter->size[0] != ob_iter->size[1] || ob_iter->size[1] != ob_iter->size[2]) {
+				BKE_reportf(reports, RPT_ERROR,
+				            "Selected objects need to have uniform scale. Apply Scale to object \"%s\"",
+				            ob_iter->id.name + 2);
+				goto cleanup;
+			}
+
+
 			tot_highpoly ++;
 		}
 
 		if (tot_highpoly == 0) {
 			BKE_report(reports, RPT_ERROR, "No valid selected objects");
-			op_result = OPERATOR_CANCELLED;
-
 			goto cleanup;
 		}
 		else {