BugFix:  - the upper block must dominate the block, else we cannot fuse    upper and lower block
BugFix:
 - the upper block must dominate the block, else we cannot fuse
   upper and lower block

[r26899]

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