QmlProfiler sometimes fails to start QmlScene

Steps to reproduce:

• make sure you have a kit using Qt5
• create a simple Qt Quick 2 UI

Not sure if the following 2 steps are necessary as well...

• create another kit using Qt5 (maybe even a clone)
• assign this to the project as well

• switch to 'Analyze'
• start profiling
• stop profiling by clicking into the 'Hello World' app
• start again profiling
• stop by hitting 'Stop profiling'
• (maybe switch the used kit and) start over at start profiling