LU-1032 build: Add Lustre DKMS spec file

LU-1032 build: Add Lustre DKMS spec file

Add a lustre-dkms.spec file which can be used to distribute dkms
style Lustre modules.  The spec file is originally based on the
generic dkms template and the default behavior is as follows:

* Disable ldiskfs osd support.  The ldiskfs packages currently
  cannot be built reliably against arbitrary kernels and are
  therefore disabled by default.

* Enable zfs osd support.  ZFS dkms packages are hosted at
  http://archive.zfsonlinux.org/{epel,fedora}/{release}/ and
  are compatible once LU-3117 is merged in to the Lustre source.

* Some of the default Lustre build options can be changed by
  setting parameted in the /etc/sysconfig/lustre config file.
  Going forward the options can be extended as needed.  The
  currently supported options are:

    * LUSTRE_DKMS_DISABLE_CDEBUG=y|N
    * LUSTRE_DKMS_DISABLE_TRACE=y|N
    * LUSTRE_DKMS_DISABLE_ASSERT=y|N
    * LUSTRE_DKMS_DISABLE_STRIP=y|N

* A build target was not added for the lustre-dkms.spec file.
  To create lustre dkms packages you must manually invoke rpmbuild.

    ./configure --enable-dist
    make dist
    rpmbuild -bs lustre-dkms.spec lustre-x.y.z.tar.gz
    rpmbuild --rebuild lustre-dkms-x.y.z-r.dist.src.rpm

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Bruno Faccini <bruno.faccini@intel.com>
Change-Id: I870f362b8948d5cd28a8dccd98b565e38ad2da7c
Reviewed-on: http://review.whamcloud.com/6019
Tested-by: Jenkins
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Brian J. Murrell <brian.murrell@intel.com>