pool: reorder ip addresses returned to NFS client

according to NFS spec pool client can select a best matching IP
address from the list available IP addresses of the pool.

Nevertheless, current client implementation in RHEL-6 takes first
one from the list and, some times, makes a wrong choice for mutihomed
pools.

This change will put 'expected correct' interface as a first element
of the returned list.

Ticket: #8404
Acked-by: Gerd Behrmann
Target: master, 2.11, 2.10, 2.9, 2.8, 2.7, 2.6
Require-book: no
Require-notes: no
Merge pull request #1131 from kofemann/no-nfs-multipath-2.6

 pool: reorder ip addresses returned to NFS client