Fix breaking change introduced in the main tree with a commit
7519a36774ca ("base-files,procd: add generic service status") where the
old service `status` callback function doesn't work anymore and needs to
be renamed to `status_service`.  This name was chosen for consistency
with start and stop function callbacks, which are using `start_service`
and `stop_service` naming schemes.

While at it, fix whitespace issues in the status_service as well.

Ref: http://lists.infradead.org/pipermail/openwrt-devel/2019-September/019035.html
Reported-by: Dirk Brenken <dev@brenken.org>
Signed-off-by: Petr Štetiar <ynezz@true.cz>