LU-10391 ptlrpc: pass net num to ptlrpc_uuid_to_connection

LU-10391 ptlrpc: pass net num to ptlrpc_uuid_to_connection

Rather than passing a nid to indicate which net to choose,
pass just the net number.  This will make it easier to convert to
'struct lnet_nid'.

Also change ptlrpc_uuid_to_peer() to take the refnet as an explicit
argument, rather than embedding in in the peer pid.

This makes the refnet test more obvious, and removes the (strange)
need to test the address part against zero.

Signed-off-by: Mr NeilBrown <neilb@suse.de>
Change-Id: I0650760a59342f5ac245cc14011452e436ef8e4c
Reviewed-on: https://review.whamcloud.com/44637
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Frank Sehr <fsehr@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Chris Horn <chris.horn@hpe.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>