lirc-modules: do not set FILES_${PN}

The module class automatically generates the kernel-module-lirc-* packages
and a lirc-modules meta package, but if we set the FILES manually the
kernel-module- packages do not get generated, causing rootfs failure.
gst-plugins: work arround for mediaserver image dependencies

Set the ALLOW_EMPTY flag on "1" for the gst-plugins*glib
and gst-plugins*apps packages.
The flag for gst-plugins*meta has already been set in poky.

Signed-off-by: Emilia Ciobanu <emilia.maria.silvia.ciobanu@intel.com>