Version negotiation thwarted by proto=udp mount option

[Tom Horsley <tom.horsley@ccur.com>]

This is from redhat bugzilla https://bugzilla.redhat.com/show_bug.cgi?id=1049032

I was asked to send mail here to see what nfs devs think about the problem.

I had the "proto=udp" option on some NFS mount lines in my fstab.
It was there because previous versions of nfs-utils apparently
ceased being able to talk to old servers at one point in time.
This option worked fine and got me connecting to the old servers.

Now a new nfs-utils came along and tries NFSv4 by default
first thing. That always rejects the mount options because
it doesn't support proto=udp at all. This leads the nfs-utils
to error out without trying a different version, so basically
my working fstab ceased to work.

I made it work again by changing to nfsvers=3 instead of
proto=udp. (But nfsvers=3 wasn't working at some point,
which was why I used proto=udp :-).