LU-14668 lnet: Peers added via kernel API should be permanent

LU-14668 lnet: Peers added via kernel API should be permanent

The LNetAddPeer() API allows Lustre to predefine the Peer for LNet.
Originally these peers would be temporary and potentially re-created
via discovery. Instead, let's make these peers permanent. This allows
Lustre to dictate the primary NID of the peer. LNet makes sure this
primary NID is not changed afterwards.

Test-Parameters: trivial
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Signed-off-by: Chris Horn <chris.horn@hpe.com>
Change-Id: I3f54c04719c9e0374176682af08183f0c93ef737