[wsgi] the spec says wsgi.url_scheme *must* be provided
No need to be defensive, anything else is a bug in the gateway.
option_group_changed('port', 'main', 'web')
option_group_changed('query-log-file', 'main', 'web')
option_group_changed('profile', 'main', 'web')
option_group_changed('max-post-length', 'main', 'web')