Apply dolorous' patch to fix incorrect handling of nets monsters

leave behind when blinking or teleporting. (Thanks.)

git-svn-id: https://crawl-ref.svn.sourceforge.net/svnroot/crawl-ref/trunk@3158 c06c8d41-db1a-0410-9941-cceddc491573

Created by  j-p-e-g  on December 30, 2007
GMCNF7YBSN7WQJNHSF3RV2NTHTVP4TABCNP7S26UEIHPAKNCPWGAC
Change contents