In masquerade views, don't use redirect location if it's not safe
In masquerade views, don't use redirect location if it's not safe

This applies to locations pulled from parameters or the referrer. Since
these could be set to something malicious, we need to check them before
redirecting to them. If they're bad, we fall back to the default
location in the settings.

wylee/django-arcutils,PSU-OIT-ARC/django-arcutils,PSU-OIT-ARC/django-arcutils,wylee/django-arcutils