remove extraneous mountlist_add/del calls and change remaining ones to use IP addresses

remove extraneous mountlist_add/del calls and change remaining ones to use IP addresses

Neil suggested a patch to change the mountlist_add and mountlist_del calls to
use IP addresses instead of the names returned by client_compose based on a
command line option flag.

I don't see any real reason to put client_compose strings into the rmtab, so
this patch makes it so that it adds IP addresses instead of those strings to
the rmtab by default.

It also removes all mountlist_add calls that are being done from kernel cache
routines. My main concern there is NFSv4. We don't seem to make any upcalls to
mountd on NFSv4 unmounts, and I don't see a way to reliably remove NFSv4
entries. So, I figured I'd stick with having mountlist_add only called when
a v2 or v3 mount call is made, and mountlist_del called only on the
corresponding unmount call.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Neil Brown <neilb@suse.de>