[WIP] Avoid harmful restart of services in master and slave recipes

Avoid harmful restarting services in master and slave recipes stated in #18.

`mesos-[master|slave]` will be (re)started when
* initial installation of mesos, or
* `mesos-[master|slave]-env.sh has been changed.
  * _even if user choose installation type 'mesosphere', this recipe creates the file for `mesos-[start|stop]-cluster.sh` script._
`notifies` attribute in `template` resource will notify to the resource __only when__ chef detected some changes between original contents and rendered one. 

> Is one for the upstart conf and the other for restarting the actual service?

Yes, I think so.  `:reload` signal would raises something like `initctl reload-configuration` and `:restart` would raises service restart literally.

I did manual check this by `vagrant up` and `vagrant provision`.  After that, process ids of `mesos-master` and `mesos-slave` aren't changed.  And then, I tried `vagrant provision` after changing `log_dir`, I saw different process ids.