Bug 1104301 - Re-disable this test on linux after an accidental reenabling. r=me

testing/marionette/client/marionette/tests/unit/unit-tests.ini

@@ -132,6 +132,6 @@ browser = false
 b2g = false
 [test_set_window_size.py]
 b2g = false
-[test_set_frame_timeout.py]
 skip-if = os == "linux" # Bug 1085717
+[test_set_frame_timeout.py]
 [test_with_using_context.py]