[Podcasts] Fix cancelling download being slow
[Podcasts] Fix cancelling download being slow

It was actually continuing the download until finished, and then
discarding the results (BGO #605624)

Dynalon/banshee-osx,mono-soc-2011/banshee,directhex/banshee-hacks,ixfalia/banshee,Dynalon/banshee-osx,dufoli/banshee,babycaseny/banshee,dufoli/banshee,babycaseny/banshee,GNOME/banshee,ixfalia/banshee,allquixotic/banshee-gst-sharp-work,petejohanson/banshee,ixfalia/banshee,arfbtwn/banshee,mono-soc-2011/banshee,dufoli/banshee,directhex/banshee-hacks,ixfalia/banshee,mono-soc-2011/banshee,arfbtwn/banshee,Carbenium/banshee,Carbenium/banshee,allquixotic/banshee-gst-sharp-work,babycaseny/banshee,GNOME/banshee,Carbenium/banshee,petejohanson/banshee,stsundermann/banshee,Dynalon/banshee-osx,arfbtwn/banshee,babycaseny/banshee,lamalex/Banshee,dufoli/banshee,stsundermann/banshee,Dynalon/banshee-osx,GNOME/banshee,directhex/banshee-hacks,petejohanson/banshee,lamalex/Banshee,directhex/banshee-hacks,petejohanson/banshee,Dynalon/banshee-osx,babycaseny/banshee,GNOME/banshee,GNOME/banshee,mono-soc-2011/banshee,Dynalon/banshee-osx,arfbtwn/banshee,allquixotic/banshee-gst-sharp-work,mono-soc-2011/banshee,ixfalia/banshee,Dynalon/banshee-osx,arfbtwn/banshee,stsundermann/banshee,petejohanson/banshee,dufoli/banshee,dufoli/banshee,lamalex/Banshee,GNOME/banshee,petejohanson/banshee,stsundermann/banshee,dufoli/banshee,GNOME/banshee,allquixotic/banshee-gst-sharp-work,Dynalon/banshee-osx,arfbtwn/banshee,allquixotic/banshee-gst-sharp-work,ixfalia/banshee,GNOME/banshee,lamalex/Banshee,lamalex/Banshee,stsundermann/banshee,mono-soc-2011/banshee,Carbenium/banshee,babycaseny/banshee,babycaseny/banshee,directhex/banshee-hacks,directhex/banshee-hacks,stsundermann/banshee,stsundermann/banshee,babycaseny/banshee,dufoli/banshee,Carbenium/banshee,Carbenium/banshee,arfbtwn/banshee,stsundermann/banshee,ixfalia/banshee,ixfalia/banshee,arfbtwn/banshee,allquixotic/banshee-gst-sharp-work,lamalex/Banshee,mono-soc-2011/banshee