RM: package no longer needed

lazr.enum was packaged for the benefit of lazr.restful (see bug 535135), which was removed from the archive a while ago. As far as I can see lazr.enum no longer has any reverse-dependencies, and it doesn't seem worth keeping it in the archive.

This is currently on the list of Ubuntu-specific Python 2 binary packages. I've just uploaded a new release to PyPI that adds Python 3 support (version 1.2), and I considered packaging it for Ubuntu. However, since it has no reverse-dependencies it doesn't seem worth spending the time to do that.

(FWIW, Launchpad itself does still use lazr.enum, and for that matter lazr.restful, but it does so via virtualenv and pip rather than using the packages from Ubuntu, so Launchpad's use of lazr.enum doesn't need to be a blocker to removing it.)