LU-1812 kernel: 3.7/FC18 server patches

LU-1812 kernel: 3.7/FC18 server patches

This patch extends lustre server support to FC18 running a
3.7.2-201 kernel with a ZFS backend. At this time ldiskfs
is not supported on FC18. This patch provides block level
performance optimizations and the ability to simulate fail
over for ldiskfs when it is provided. The jbd2-jcberr patch
was not ported to these new platforms for reasons described
in LU-433.

Signed-off-by: James Simmons <uja.ornl@gmail.com>
Change-Id: I2a86d7ca4e068686372eb74f85b1443d24e245c4
Reviewed-on: http://review.whamcloud.com/4649
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Yang Sheng <yang.sheng@intel.com>