test-disabled-1-1-tubes.py: add error message when asserting False
test-disabled-1-1-tubes.py: add error message when asserting False

freedesktop-unofficial-mirror/telepathy__telepathy-salut,freedesktop-unofficial-mirror/telepathy__telepathy-salut,freedesktop-unofficial-mirror/telepathy__telepathy-salut,freedesktop-unofficial-mirror/telepathy__telepathy-salut