mdadm fixes to make sure boot sequence all works properly.

- boot.md - simplify boot.
As array assembly is done by udev, it shouldn't
be done by boot.md. This will avoid some problems
with arrays getting started degraded.

- Make-IRs-and-run-work-properly-for-containers.patch
- mdmon-honour-offroot-again.patch
Upstream fixes

- config-set-auto_seen-after-processing-the-auto-line.patch
Fix bug which causes "AUTO -all" in mdadm.conf
in initrd to be ignored, so array might be
auto-assembled too early.

- mkinitrd-boot.sh: simplify boot sequence by relying
completely on udev running "mdadm -I". Thus
mkinitrd-boot.sh needs to do very little.
The devfunction script in the mkinitrd package has
been modified to start newly degraded array after
a suitable timeout.
- mkinitrd-setup.sh:
- don't save md_devs as it isn't used any more
- allow md device names like "/dev/md_foo" which will
need to be supported in due course.

- mkinitd-boot.sh: Clear {root,resume}_major variable
If multipath is in use, md is always on top of it. Therefore, the root
device is always an md device. (bnc#786526)