Fix inverted logic (oops).

git-svn-id: https://crawl-ref.svn.sourceforge.net/svnroot/crawl-ref/trunk@8774 c06c8d41-db1a-0410-9941-cceddc491573

Created by  dolorous  on January 26, 2009
4FJTZNKO5X5K7O2PWMEQT3YJG22CVDPNIOTRV65XLZQROHFR3RRQC
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