Update kmodule submodule

From commit log:

commit 881308c21a9039e47094c87b7b676001d015ae26
Author: John Morris <john@zultron.com>
Date:   Thu May 1 03:05:02 2014 +0200

    Fix typo breaking Makefile
Update git/linux/debian submodule

From commit log:

commit 0a83b602e6fb9a1d65b1c8ff08b672b11b232395
Author: John Morris <john@zultron.com>
Date:   Tue Apr 29 18:41:49 2014 +0200

    Update Config-Xeno submodule:  Add CONFIG_PREEMPT_NONE

    From submodule commit log:

      Gilles's recommendation:
      http://permalink.gmane.org/gmane.linux.real-time.xenomai.users/18499

        No, as I said, in my experience, turning CONFIG_PREEMPT off,
        setting it to CONFIG_PREEMPT_NONE, results in shorter worst case
        latencies for Xenomai.
Fix pbuild/build-kmodules.sh script

No ppa at this point, so use dpkg instead of apt-get to install
linux headers and xenomai patch packages