Historically, we've shipped a reviewboard.wsgi file in the generated

site directory, which could be passed to some WSGI implementations. This

wasn't suitable for all, though, as some servers (like gunicorn) want an

actual module path and not a standalone file on the filesystem.
It was also bad for maintenance. We've already had to write patching

logic in rb-site to update parts of this for Django 1.11 in

release-4.0.x. Making more invasive changes down the road is even more

work.
Now we ship an actual importable reviewboard.wsgi module that contains

all the setup. It only needs a REVIEWBOARD_SITEDIR environment

variable to work, which can be set by a server.
The generated htdocs/reviewboard.wsgi file is now simpler, just

setting this variable and importing from the new reviewboard.wsgi.
Since this is landing on release-3.0.x, no existing configurations

will be updated. Things will continue working as-is. The plan is to

update release-4.0.x to move existing configurations over to this

module.

Tested an Apache install with the old reviewboard.wsgi file forwarding

to the reviewboard.wsgi module.
Tested a Gunicorn install with the new reviewboard.wsgi module.