Proxito: check if attribute exists

[stsewd]

Ref https://sentry.io/organizations/read-the-docs/issues/2216431985/?environment=production&project=148442&query=is%3Aunresolved+host_project_slug&statsPeriod=14d

[ericholscher]

Do we know why this is happening? Did we add a new code path that isn't setting this?

[stsewd]

Do we know why this is happening? Did we add a new code path that isn't setting this?

@ericholscher don't think this is new, looks like it happens when we hit this code

readthedocs.org/readthedocs/proxito/middleware.py

Lines 184 to 191 in 4d35b82

	if (
	skip
	or not settings.USE_SUBDOMAIN
	or 'localhost' in request.get_host()
	or 'testserver' in request.get_host()
	):
	log.debug('Not processing Proxito middleware')
	return None

So, anything with testserver or localhost in the host (https://one-testserver.readthedocs.io/) would skip setting the host_project_slug. I guess we should check if for an exact match instead of using in, or remove that check? not sure why we do that. But looks like there are other places where we could be returning early before setting the project_host_name thing.