Fix Dropbear symlinks to dropbearmulti
Thanks to Adrian Grigo for pointing this out. http://lists.cross-lfs.org/pipermail/clfs-dev-cross-lfs.org/2011-April/000963.html
Symlinks need to point to /usr/bin/dropbearmulti rather than ${CLFS}/usr/bin/dropbearmulti as ${CLFS} won't be a real path inside the target once booted.