Deleting all instances of the path from the URL meant that referers like
`https://learning.edx.org/` were turned into `https:learning.edx.org`. The
solution here is to use `urlunparse` to put the URL back together, but only
with the desired components (scheme and authority/netloc).
This relates to our previous upgrade to django-cors-headers 3.x, which
changed to use origins instead of domains in its whitelist setting:
36df86d829 (diff-811d60a3e1d60ff694eace0242e77d6b810d8e9c63c36d7b3c2591a08ebbb94bR58)
Added regression test (fails on master, passes on branch.)
Also:
- Replace word "domain" with "origin" in few places to use the correct
term. (We should probably change this more broadly in names and comments
in this module as some point.)
- Simplify logging to just output what we know, and not try to recapitulate
the logic too much.
ref: BOM-2961
4efd2d161a