x11/lightdm: Update to 1.30.0, fix crash and change default config
This update addresses a crash in lightdm, related to the way the
user environment for the lightdm process is setup in src/process.c.
The configuration option in lightdm.conf for locked memory is now
honoured - the default configuration has been updated to disable this,
and pkg-message has been updated to reflect this change.
Changes this release: