Bug 800347 - Try clearing RPCChannel in the destructor so that the dequeue task is cancelled properly. r=dvander, a=akeybl
Bug 900711 - '~nsIThreadPool can run the event loop if shutdown has not been
called'. r=ehsan. a=lsblakk

(transplanted from 7236065ca5bfae6326a9b96e0ea633395904405b)

--HG--
extra : transplant_source : r6%06%5C%A5%BF%AEc%26%A9%B9n%0E%A639Y%04%40%5B
Bug 900711, fix bustage a=lsblakk

(transplanted from 08b4c4071214bc7a9a56bb61243fd36bd082c143)

--HG--
extra : transplant_source : %08%B4%C4%07%12%14%BCz%9AV%BBa%24%3F%D3k%D0%82%C1C