Observer: add Requests_Satisfied parameter
Observer: add Requests_Satisfied parameter

We could stuff this into the generic a{sv}, but while we're breaking API
anyway...

Reviewed-by: Robert McQueen <16d5fb26f6035913e0e337118425aefb8f6ec9c7@collabora.co.uk>
Reviewed-by: Sjoerd Simons <1371fd10dd05a897e5b55dc6ae4fbafa1f84c6ec@collabora.co.uk>
Reviewed-by: Will Thompson <5822fdda638242a44ccfa68f146ccf6f257c5cbd@collabora.co.uk>

TelepathyIM/telepathy-spec,freedesktop-unofficial-mirror/telepathy__telepathy-spec