fix minesweeper test to use assertRaisesRegex instead of broken context check
fix minesweeper test to use assertRaisesRegex instead of broken context check

behrtam/xpython,orozcoadrian/xpython,outkaj/xpython,N-Parsons/exercism-python,ZacharyRSmith/xpython,smalley/python,exercism/python,Peque/xpython,Peque/xpython,pheanex/xpython,jmluy/xpython,de2Zotjes/xpython,ZacharyRSmith/xpython,rootulp/xpython,pombredanne/xpython,pheanex/xpython,rootulp/xpython,exercism/xpython,wobh/xpython,oalbe/xpython,outkaj/xpython,exercism/xpython,behrtam/xpython,exercism/python,orozcoadrian/xpython,wobh/xpython,jmluy/xpython,mweb/python,mweb/python,N-Parsons/exercism-python,pombredanne/xpython,oalbe/xpython,smalley/python,de2Zotjes/xpython