[OpenAFS] vos move "forgot" to remove .backup volume.

[Harald Barth]

> I'd dare the conjecture that creating the transaction in the
> volserver failed, possibly because some other transaction such as a
> trivial "vos listvol" was going on, and "vos move" forgot to tell
> you about it.

That seems 

> As we do frequent "vos listvols" on all our servers for monitoring
> we used to see problems with that, for example during the nightly
> "vos backupsys".

We do "vos parti" from monitoring. Not sure about listvol. Because of the long time it took, we have
changed from

vos backupsys
vos dump vol1; vos dump vol2; ....

to

vos backup vol1; vos dump vol1; vos backup vol2; vos dump vol2...

> I'll submit a patch as it is generally useful - the brutal rather
> than the elegant approach: sleep and retry a couple of times in
> NewTrans(). It got delayed a bit as it corrected a locking problem
> as well in 1.4.6 still which collided with the correction of that
> problem in 1.4.8.

That is not elegant, but it may solve some problems now. But probably
I should look a little bit closer at vos move, too.

> But it's a conjecture anyway: there may still be something else.

As always. Thanks :)

Harald.