On fades, only unhighlight if already highlight.

[kadams54]

In added services, when you fade a service, it should also toggle
highlights off. The original code would toggle the highlight flag
regardless of whether it actually needed it, which causes problems
downstream in the code.

[kadams54]

QA

1. Deploy the MongoDb Bundle.
2. Deploy/commit/autoplace mysql.
3. Highlight Shard 3 (works as expected).
4. Fade Shard 2 (works as expected).
5. Fade Mongos and verify that mysql does not become visible again.
6. Highlight Mysql and make sure everything works as expected.
7. Fade Mysql and verify that the highlight is toggled off.

[hatched]

👍 QA OK
I can't seem to find any more issues, we might have it this time :)

[jujugui]

Test PASSed.
Refer to this link for build results: http://ci.jujugui.org:8080/job/juju-gui/2221/

[makyo]

👍 Thanks!

[kadams54]

Another one bites the dust…

[jujugui]

Build failed: Attempt to land pull request failed
build url: http://ci.jujugui.org:8080/job/juju-gui-merge/783

[kadams54]

NPM failure. Trying again.

[jujugui]

Status: merge request accepted. Url: http://ci.jujugui.org:8080/job/juju-gui-merge