When setting a random wandering target, make sure it's in bounds by using

X_BOUND_2 and Y_BOUND_2 rather than GXM and GYM.

Assert that _handle_behaviour() has set a valid target.

git-svn-id: https://crawl-ref.svn.sourceforge.net/svnroot/crawl-ref/trunk@8180 c06c8d41-db1a-0410-9941-cceddc491573

Created by  zelgadis  on January 3, 2009
WBRAEO5JU2JNLWCSBCHQGVSB64FJBCXLT5HCRRDM2ZBSZSOZNEIQC
Change contents