update should clean up/warn about jockey

Binary package hint: jockey-common

Hi,
   I'm a regular on #ubuntu+1 and a very common failure for people trying alpha/betas over the last few releases
is that because the proprietary drivers aren't available until late in the release cycle, people running with proprietary drivers
break everything and often end up unbootable or at a text prompt.

  I think what should happen is that update-manager and do-release-upgrade should check with jockey and see if the thing they are upgrading to has the proprietary drivers, and if not then it should .... hmm well there's a good question.

I can see that it should at least warn the user; but I see 2/3 possibilities:
  1) The destination has the proprietary driver anyway - probably no need to warn
  2) The destination doesn't have the proprietary driver:
     a) The destination now has an open driver - so the proprietary driver should be removed, at least the user should be warned.
     b) The destination doesn't have an open driver - the user needs warning, probably the proprietary driver needs warning since it probably won't work on the destination.

For (2) the user definitely needs to be warned, if it doesn't autoremove the package for them it should give some explanation of what to do.

Other side effects may need to happen as well, e.g. moving xorg.conf out the way on removing fglrx.

Either way it needs something more than at the moment where people are left with a broken system without realising it.

Dave