Fixed building of Elk & dependencies
Create elk virtualenv with PyOpenSSL
Now generating proper Elk release.

We're now generating a proper ELk release, and cleaning out it's source
& build files from the machine.  Also including PyOpenSSL in that
release.  This should mean child dockerfiles are clear to deal with
virtualenvs as they see fit - otherwise we'd have to force them to use
the venv we created in this dockerfile.