LU-3297 lov: convert magic to host-endian in lov_dump_lmm()

In lov_dump_lmm(), convert the lmm_magic from little-endian to
host-endian byte order before the switch statement, as the other
lov_dump_xxx() and lov_verify_xxx() functions already do.  Remove the
unused macro LMM_ASSERT().

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Change-Id: Icfa52f3043aaa13b0d0cc34f5be2f59792c3787e
Reviewed-on: http://review.whamcloud.com/6290
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Li Wei <wei.g.li@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>