This is the second iteration of this patch. The only difference here

is that this one has default_value call nfs_nfs_proto_family regardless
of whether IPV6_SUPPORTED is set.

When IPv6 is enabled, the Proto= config file option is treated as a
netid, and the address family for lookups is selected based on that
setting. The Defaultproto= option however still only affects the
protocol setting for the sockets (IPPROTO_*) and not the address family.

This patch makes it so that if someone sets the "Defaultproto=" option
in the nfsmount.conf, it's used to determine the default address family
for lookups as well as the protocol type.

This gives users a way to force a particular address family to be used
universally for mounts and brings the behavior of the Defaultproto=
option in line with the Proto= option.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve Dickson <steved@redhat.com>