classes/image: disable pam nullok_secure with debug-tweaks
If you want passwordless logins to work with pam enabled, then you can't
have "nullok_secure" enabled on pam_unix entries. Add some
postprocessing to change these to "nullok" when debug-tweaks is in
IMAGE_FEATURES, in order to make passwordless logins with PAM work
again.
Fixes [YOCTO #5973].
Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
