REL-2043: QPT startup error

The Activator was requesting the KeyChain service synchronously leading to an NPE
For some reason this hit us on the last release. It has been changed to use a ServiceTracker and tested on Linux and OSX

@tpolecat Could you check if the initialization and cleanup seem correct

I think is odd that Activator implements AWTEventListener, I'd rather use an inner class, any opinions?