LU-8955 ptlrpc: manage SELinux policy info at connect time

LU-8955 ptlrpc: manage SELinux policy info at connect time

At connect time, compute SELinux policy info on client side, and
send it over the wire.
On server side, get SELinux policy info from nodemap and compare
it with the one received from client.

Signed-off-by: Sebastien Buisson <sbuisson@ddn.com>
Change-Id: I9b4a206455f2c0b451f6b3ed7e3a85285592758e
Reviewed-on: https://review.whamcloud.com/24422
Reviewed-by: Patrick Farrell <pfarrell@whamcloud.com>
Reviewed-by: Li Dongyang <dongyangli@ddn.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Tested-by: Jenkins
Tested-by: Maloo <maloo@whamcloud.com>