roster.c: explain the handle ref for roster_edited_cb
roster.c: explain the handle ref for roster_edited_cb

jku/telepathy-gabble,mlundblad/telepathy-gabble,community-ssu/telepathy-gabble,community-ssu/telepathy-gabble,mlundblad/telepathy-gabble,Ziemin/telepathy-gabble,Ziemin/telepathy-gabble,Ziemin/telepathy-gabble,jku/telepathy-gabble,mlundblad/telepathy-gabble,jku/telepathy-gabble,community-ssu/telepathy-gabble,Ziemin/telepathy-gabble,community-ssu/telepathy-gabble