Per Haran's suggestion, simplify by using monsters::mindex().

git-svn-id: https://crawl-ref.svn.sourceforge.net/svnroot/crawl-ref/trunk@8606 c06c8d41-db1a-0410-9941-cceddc491573

Created by  dolorous  on January 19, 2009
H6BKDO7FWEURT2BOJWZ55GKJMZ6MFJP5BCDVZVZJUJAUNYDXQOPAC
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