Forward-port minor shaft trap tweaks for pacified monsters from 0.5

branch r9858.

git-svn-id: https://crawl-ref.svn.sourceforge.net/svnroot/crawl-ref/trunk@9859 c06c8d41-db1a-0410-9941-cceddc491573

Created by  dolorous  on May 31, 2009
5BDBWUAXTI7UQGQ3U6XMSKDQXSE3WVFZBLG22CJYNMTAERWFYQEAC
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