Fixed other possible crashes due to forceful subscription termination

Ignore-this: 1334d4293f2ad2abbaaee36e4c98a789

darcs-hash:20100901204005-56b4d-c7fff53e4df85150a5bddc05f8d821e3990c2e45
Use the reactor to push subscribe command to the channel

Ignore-this: 836c220d2ac6418781538a5e3e955b51

darcs-hash:20100901204637-56b4d-121f2002d590aa50fb81a3f044afbcb98386049d