[pvrusb2] Persistent device nodes

[Andrew Cagney]

I've been using it for Ubuntu 11.10 & 12.04;  I've a fuzzy memory that
I had to tweak it after upgrading from 11.04 -> 11.10 (I don't have
that version around).

> So this is code for: doesn't work on my system, which is running Ubuntu
11.04.

The output from:
   udevadm test $(udevadm info --query=path --name=/dev/video0)
can help with debugging (or you can stick with what you already had working :-)