Fixed QThreadPool globalInstance ownership rules.
Fixed QThreadPool globalInstance ownership rules.

Fixed QThreadPool start, tryStart ownership rules.

Fixes bug #927.

Reviewer: Lauro Moura <0a8fa8edd22fa9fe5368dd0f405da07e619faa6c@openbossa.org>
          Hugo Parente <hugo.lima@openbossa.org>

enthought/pyside,RobinD42/pyside,IronManMark20/pyside2,BadSingleton/pyside2,pankajp/pyside,pankajp/pyside,M4rtinK/pyside-bb10,qtproject/pyside-pyside,M4rtinK/pyside-android,PySide/PySide,M4rtinK/pyside-android,qtproject/pyside-pyside,gbaty/pyside2,gbaty/pyside2,IronManMark20/pyside2,RobinD42/pyside,enthought/pyside,pankajp/pyside,IronManMark20/pyside2,enthought/pyside,qtproject/pyside-pyside,IronManMark20/pyside2,M4rtinK/pyside-bb10,M4rtinK/pyside-bb10,gbaty/pyside2,PySide/PySide,M4rtinK/pyside-bb10,BadSingleton/pyside2,pankajp/pyside,RobinD42/pyside,enthought/pyside,RobinD42/pyside,PySide/PySide,enthought/pyside,BadSingleton/pyside2,BadSingleton/pyside2,RobinD42/pyside,IronManMark20/pyside2,M4rtinK/pyside-android,qtproject/pyside-pyside,PySide/PySide,qtproject/pyside-pyside,BadSingleton/pyside2,M4rtinK/pyside-android,M4rtinK/pyside-bb10,pankajp/pyside,gbaty/pyside2,RobinD42/pyside,RobinD42/pyside,PySide/PySide,M4rtinK/pyside-android,M4rtinK/pyside-bb10,gbaty/pyside2,enthought/pyside,M4rtinK/pyside-android,enthought/pyside