iso9660 used LINUX26_IMAGE_PATH, which got renamed. Adjust to match
the new name.
Reported-by: Sven Neumann <s.neumann@raumfeld.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Use rootfs-* rather than *-root, to match the convention used under
package/ and which fits with the ROOTFS_*_ variables.
This will also help with the host dependencies.
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>