tar2vm: use -s Luke

This is a partial backport of g4918019 commit:
"Really no need to test and sleep when there's sync mode"
vm.mk: use sysvinit

I don't see any reason to use systemd within VM images,
and it would stick its journal as a syslog implementation
when not ditched explicitly :-/

(backport)
vm.mk: vm/net should use/repo

IOW one has every right to expect that package manager
is set up already in a networked virtual machine.

(backport)
p7.mk: added vm/net alias

vm/altlinux-p7-vm-net is yet another bridge...

(backport)
vm.mk: use led-ws kernel instead of un-def

It's the most compact "generic" kernel available
in Sisyphus and some branches; led-vs might have
been more suitable but it's not supported within
p7/branch (current stable).
tar2vm: append to MODULES_PRELOAD, do not clobber

Thanks glebfm@ for spotting that it's = instead of +=
as it goes in all the other places; I remember no good
reason to overwrite the potentially preexisting contents.

(backport)
tar2vm: use UUID, prepare for virtio as well

Thanks glebfm@ and sem@ for reminding me about UUID;
the only hardwired thing left is "sda" which *will*
break for virtio_blk case when updating the kernel;
fixing this up in a firsttime script might be due
but the diagnostics should be pretty informative.

These images boot with SATA emulation, virtio_blk setup
(plain virtio disk), and virtio_scsi setup available in
newer qemu/kvm and libvirt; one is advised to read
http://linux-kvm.com/content/virtio-scsi
vm.mk: extend vm/net base image size to 5 Gb

qemu-img makes use of sparse files so the image will take up
reasonable space when handled appropriately (and compress nicely
as well); making images of minimal size is going to result in
grave usage problems starting with apt-get update hitting ENOSPC.
1.0.3-alt0.M70T.1

- vm fixes/backports
gear-store-tags