[1964967] Fixing issue where the abyss and the labyrinth had stale out of sight tiles on the left and right side of the screen.

git-svn-id: https://crawl-ref.svn.sourceforge.net/svnroot/crawl-ref/trunk@5549 c06c8d41-db1a-0410-9941-cceddc491573

Created by  ennewalker  on June 7, 2008
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