mel: drop old unnecessary ro-rootfs bits

oe-core has everything that was in meta-ro-rootfs.

Signed-off-by: Christopher Larson <chris_larson@mentor.com>
mel, connman: pull over last bits from meta-ro-rootfs

Signed-off-by: Christopher Larson <chris_larson@mentor.com>
Merge pull request #334 from kergoth/ro-rootfs-updates

Migrate last remaining bits from meta-ro-rootfs