danga.com -> memcached.org in a few spots.
fix infinite loop regression in 1.4.18

Seems that a closed connection can fire off extra events sometimes? There
might still be another bug lurking.
there was no infinite loop in prev commit

or at least reasonably sure. hopefully I don't have a third commit shortly
backtracking this backtrack. The other one was most likely caused by a bad
build, given that event_del() was most certainly called but the event was
still linked in the libevent queue somehow.