Code review comment for lp://staging/~hatch/juju-gui/num-units-1253113

Reviewers: mp+197597_code.launchpad.net,

Message:
Please take a look.

Description:
Fix: Removing units throws notification error

Removing units in the sandbox and in a real environment no longer
always throws an error.

To QA:
Sandbox:
Deploy a service with 10 units, change it to 1 unit, it should scale
down to 1.

Real environment:
Deploy a failtester service with 3 units in the GUI
after they are up scale it down to 1, they should scale down without
notifications.

https://code.launchpad.net/~hatch/juju-gui/num-units-1253113/+merge/197597

(do not edit description out of merge proposal)

Please review this at https://codereview.appspot.com/36690043/

Affected files (+118, -7 lines):
   [revision details]
   app/store/env/fakebackend.js
   app/store/env/sandbox.js
   test/test_fakebackend.js
   test/test_sandbox_go.js