QMacStyle: Always draw status bar in active state if the window is main.

On OS X, most controls are drawn active or inactive based on their
window's main state, NOT its key ("active" in Qt) state.

Change-Id: If447d0a537bc594978f7202e7888ceacb54ec8fa
Reviewed-by: Morten Johan Sørvig <morten.sorvig@digia.com>