wocky-xmpp-scheduler-test: factor out close_connection()
wocky-xmpp-scheduler-test: factor out close_connection()

noonien-d/wocky,freedesktop-unofficial-mirror/wocky,noonien-d/wocky,freedesktop-unofficial-mirror/wocky,noonien-d/wocky,freedesktop-unofficial-mirror/wocky