www/py-django-mezzanine: Update to 4.2.2, Mark Un'BROKEN

• Update PORTVERSION and distinfo checksum (4.2.2)
• Update RUN_DEPENDS. In particular, switch to Django 1.8 and mark un'BROKEN accordingly
• Remove setup.py patch. No longer necessary.
• Enable concurrent Python installation

MFH: 2016Q4
X-MFH-With: 424630, 427770, 427772