Avoid using the handle and handle_type member
Avoid using the handle and handle_type member

Once we rewrite all the code not to use them, the handle and handle_type
private members will be removed. This first patch modifies the get/set public
functions, to retrieve the handle and handle type either from the TpChannel or
from the request data.

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