only set pinned state when not already pinned
only set pinned state when not already pinned

[r16119]

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