Bug 1115410 - Remove job controls boundary

This fixes Bugzilla bug [1115410](https://bugzilla.mozilla.org/show_bug.cgi?id=1115410).

A little LHF. Since we already have the implied boundary from the adjacent Failure Summary tab(s), and they will always exist when the job panel is up, we can make the UI a little cleaner here.

Here's the before:

![jobcontrolsboundarycurrent](https://cloud.githubusercontent.com/assets/3660661/5583800/c4c5274a-904c-11e4-9e1f-e4458c813980.jpg)

Here's the after:

![jobcontrolsboundaryproposed](https://cloud.githubusercontent.com/assets/3660661/5583801/cc44a176-904c-11e4-9871-8fbb47376c85.jpg)

Here's the full control block:

![jobcontrolsboundaryall](https://cloud.githubusercontent.com/assets/3660661/5583802/d3f12020-904c-11e4-8716-77fff9f43004.jpg)

Tested on Windows:
FF Release **34.0**
Chrome Latest Release **39.0.2171.95 m**

Everything seems fine at varying sizes, job types with different numbers of controls, etc.

Adding @camd for review and @edmorley for visibility.