Fixes for a disposal runtime everytime something got flushed

http://pastebin.com/tpQWSW9P

Detailed writeup of cause: Disposal holder object was going through the loop, looking for pipes and continuing on. When it hit the outlet, the outlet ejects everything and qdel()'s the disposal holder. Holder continues processing, sees that there's nowhere else to go, and tries to emergency eject. Doing so calls a bunch of loc = null procs that runtime.
Fix: Make the processing part of the disposal holder only continue if it's active. Make the disposal holder inactive as part of Destroy().