[PATCH] use python-meh for exception reporting

[Chris Lumens <clumens redhat com>]

The following series of patches changes anaconda over to using the new
python-meh for exception handling.  I have tested this, though something is
bound to go wrong once we get all the packaging done and into a release.
Before this can be pushed, the new python-meh package needs to make it in,
though that's supposed to be in the works.

Doing this will allow me to later get rid of rhpl.exception.  I think there's
a bug and patch filed against all components that use it now.  At least, I
know I've cleaned up my code.

- Chris