Fix 2134492: mgrd not being updated in area_shift(). My bad.

git-svn-id: https://crawl-ref.svn.sourceforge.net/svnroot/crawl-ref/trunk@7066 c06c8d41-db1a-0410-9941-cceddc491573

Created by  haranp  on September 29, 2008
IC46VVFHPA3THXFEJEZH557YNLJK7ZU2E4WAZ2UYXCH4FVYROYJAC
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