mcd_keyfile_get_variant: add support for int16, uint16
mcd_keyfile_get_variant: add support for int16, uint16

If we're opportunistically migrating parameters according to
CM-specified types, we need to cope with uint16 ('q') for port numbers.

Bug: https://bugs.freedesktop.org/show_bug.cgi?id=71093
Reviewed-by: Guillaume Desmottes <f16649c7afcd84e3350287183c4ed23cb1aea57c@collabora.co.uk>

freedesktop-unofficial-mirror/telepathy__telepathy-mission-control,freedesktop-unofficial-mirror/telepathy__telepathy-mission-control,freedesktop-unofficial-mirror/telepathy__telepathy-mission-control,freedesktop-unofficial-mirror/telepathy__telepathy-mission-control