fix(scheduler/coreos): skip announcer containers for start, stop, destroy

With #1269 we stopped creating announce containers except for web and cmd
types, but we still attempt to perform actions on them for start, stop,
and destroy. This commit adds logic to wrap all of these scheduler actions
in a conditional which skips (and logs) announce operations.

TESTING: rebuild the controller
```console
$ make -C controller stop build start
```

Then, deploy an application which has either a cmd or web proctype, as
well as a non-standard type. I modified the Procfile for our
example-ruby-sinatra like so:

```
web: bundle exec ruby web.rb -p ${PORT:-5000}
clock: echo flava flavvvvvvv
```

Scale the app, start/stop processes, etc. You should see successful
operations for both, and note that the clock type has no announce
containers. The output of ```deis ps``` should always show them
as being up:

```
=== exotic-icehouse Processes

--- web:
web.1 up (v3)
web.2 up (v3)
web.3 up (v3)

--- clock:
clock.1 up (v3)
clock.2 up (v3)
clock.3 up (v3)
```

fixes #1273
closes #1275
Could you please add this space back? `flake8` would typically complain here because the import statements and the first function definition is not spaced out by two blank lines, but it passed because this file [is being skipped over](https://github.com/deis/deis/blob/master/controller/setup.cfg#L3).