LU-6086 obdclass: check peer's version for MDT-MDT connection

LU-6086 obdclass: check peer's version for MDT-MDT connection

Because new DNE/LFSCK changed some wire protocol, we cannot support
the interoperations between different version MDTs. The basic rules
for the permitted connection are:
1) The @major in the connection version should be the same;
2) The @minor in the connection version should be the same;
3) The difference of the @patch in the connection version should NOT
   more than 3.

Signed-off-by: Fan Yong <fan.yong@intel.com>
Change-Id: I9e77f305c7552ad01e92c97f1eda0756f1291d30
Reviewed-on: http://review.whamcloud.com/13285
Tested-by: Jenkins
Reviewed-by: Lai Siyao <lai.siyao@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>