Since the recovery script checks the update package before installing it, use
the package's description to indicate if the package is meant to encrypt the
rootfs or not. Also, remove the pre-install script from the ccimx6ul packages,
since the logic in the script to remove the encryption flag from the rootfs is
now in the recovery script.
https://onedigi.atlassian.net/browse/DEL-7174
Signed-off-by: Gabriel Valcazar <gabriel.valcazar@digi.com>