NLM: Set address family before calling nlm_host_rebooted()

The nlm_host_rebooted() function uses nlm_cmp_addr() to find an
nsm_handle that matches the rebooted peer.  In order for this to work,
the passed-in address must have a proper address family.

This fixes a post-2.6.28 regression introduced by commit 781b61a6, which
added AF_INET6 support to nlm_cmp_addr().  Before that commit,
nlm_cmp_addr() didn't care about the address family; it compared only
the sin_addr.s_addr field for equality.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>