sm-notify command: replace nsm_address typedef

Clean up: replace "typedef struct sockaddr_storage nsm_address" with
standard socket address types.  This makes sm-notify.c consistent with other
parts of nfs-utils, and with typical network application coding conventions.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Steve Dickson <steved@redhat.com>