review context destroy from cancel callback
review context destroy from cancel callback

huitema/getdns,smogali/getdns,dkg/getdns,glenwiley/getdns,Acidburn0zzz/getdns,huitema/getdns,smogali/getdns,dkg/getdns,smogali/getdns,shane-kerr/getdns,huitema/getdns,glenwiley/getdns,huitema/getdns,dkg/getdns,glenwiley/getdns,Acidburn0zzz/getdns,Acidburn0zzz/getdns,Acidburn0zzz/getdns,smogali/getdns,shane-kerr/getdns,glenwiley/getdns,shane-kerr/getdns,dkg/getdns,shane-kerr/getdns