Upstart provider should obey the `supports[:reload]` option

For example, Upstart jobs that run once on a certain event, like `/etc/init/hostname` and `/etc/init/passwd` don't support reload - an error code of 1 will be returned by `/sbin/reload`.

This patch makes `supports reload: false` work for a `service`, instead of ignoring it and attempting to reload an Upstart service via `/sbin/reload`.

Other trivial changes (small stuff I noticed while reading the code):
* Fix "restart" copy that should say "reload".
* Add missing test case for an exception being raised by`Chef::Provider::Service` if restart isn't supported.