LU-7543 obd: reserve connection flag OBD_CONNECT_LOCK_AHEAD

LU-7543 obd: reserve connection flag OBD_CONNECT_LOCK_AHEAD

The connection flag OBD_CONNECT_LOCK_AHEAD will be used for the
following the patch: LU-6917 LDLM lock ahead
http://review.whamcloud.com/13564

Land the connection flags to master earlier for reserving the
slot to avoid potential conflict with others.

Signed-off-by: Fan Yong <fan.yong@intel.com>
Change-Id: Ifd5d26d52336b45c962cb34a83bc3582646cfdf4
Reviewed-on: http://review.whamcloud.com/17646
Tested-by: Jenkins
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Patrick Farrell <paf@cray.com>
Tested-by: Maloo <hpdd-maloo@intel.com>