Arg: add a missing inc_irg_visited, who has deleted it?
Arg: add a missing inc_irg_visited, who has deleted it?

[r21552]

davidgiven/libfirm,MatzeB/libfirm,MatzeB/libfirm,libfirm/libfirm,8l/libfirm,8l/libfirm,killbug2004/libfirm,libfirm/libfirm,8l/libfirm,8l/libfirm,libfirm/libfirm,killbug2004/libfirm,davidgiven/libfirm,davidgiven/libfirm,killbug2004/libfirm,davidgiven/libfirm,MatzeB/libfirm,jonashaag/libfirm,killbug2004/libfirm,jonashaag/libfirm,MatzeB/libfirm,jonashaag/libfirm,libfirm/libfirm,libfirm/libfirm,jonashaag/libfirm,jonashaag/libfirm,killbug2004/libfirm,davidgiven/libfirm,8l/libfirm,davidgiven/libfirm,8l/libfirm,MatzeB/libfirm,killbug2004/libfirm,jonashaag/libfirm,MatzeB/libfirm,killbug2004/libfirm,8l/libfirm,MatzeB/libfirm,jonashaag/libfirm,davidgiven/libfirm