LU-1644 mgc: remove obsolete IR swabbing workaround

LU-1644 mgc: remove obsolete IR swabbing workaround

The OBD_CONNECT_MNE_SWAB check was added to the MGC for compatibility
with servers in the 2.2.0-2.2.55 range (in 2012) with big-endian
clients.  2.2 was not an LTS release and is no longer being used.

Remove the checks on the client for OBD_CONNECT_MNE_SWAB being set,
and assume that the server does not have this bug.  This will allow
the removal of the rest of this workaround from the server code once
there are no more clients depending on the presence of this flag.

Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Change-Id: Ie128745e3af8e9d41454e095922e0f6bc8fcab07
Reviewed-on: https://review.whamcloud.com/32087
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Jinshan Xiong <jinshan.xiong@gmail.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>