Cleanup. Also fix potential bug: Do not read link field after exchanging node.
Cleanup. Also fix potential bug: Do not read link field after exchanging node.

[r14908]

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