The drm feature solves the problem of creating a common entry
point for adding kernel drm modules for different package lists.
The need for allocation into a separate feature arose from one
parties to the need to make a switch between free and proprietary
NVIDIA driver, on the other, because of the need to add only drm
modules kernels for purposes such as use/stage2/kms and use/plymouth.

Also no more switch needed for RADEON, as only the free video driver
remains.

make-initrd-plymouth missing in squashfs results in
plymouth bootsplash not available at boot.

See-also: https://bugzilla.altlinux.org/35941

This has only been useful for plymouth feature,
and +installer shortcut included this target
for all the wrong reasons as it seems today
(thus blocking the DRM-free server installers,
for example).

I don't think we're gonna like plymouth over rescue image
anytime soon, especially when it hides the moment when shell
pops up somewhere under it without startup-rescue caring to
remove the splash.

So let's put that $(INSTALL2_BRANDING) into proper stage2
flavours only and avoid choking on missing plymouth as well.

It appeared that plymouthd.conf wasn't set up properly
thus "service plymouth stop" didn't result in anything
meaningful; thanks boyarsh@ for his help figuring this
out again.

The missing "; @:" at the end of the otherwise recipeless rule
resulted in target graph being broken; I should have checked this
when introducing these aliases (the intent was to reduce noise).

It's configured by plymouth feature when needed;
install2 bootargs support is generalized a bit
to become stage2 one as was intended anyways.

An initial draft of it was done half a year ago but several tricky
thingies had kept the code from showing up as it was rather brittle
and incomplete.

This implementation involves quite a few changes all over the place
but finally works good enough for live and installer images.

Please pay attention to the versions of these packages:
- installer-feature-setup-plymouth (0.3.2-alt1+)
- branding-altlinux-sisyphus (20110706-alt2+ if used)
- plymouth (0.8.3-alt20.git20110406+)

See also:
- http://www.altlinux.org/Branding
- http://www.altlinux.org/Plymouth