functional-tests: Disconnect writeback name-owner signal
functional-tests: Disconnect writeback name-owner signal

To avoid duplicate messages when starting/stopping the process in successive tests

hoheinzollern/tracker,hoheinzollern/tracker,outofbits/tracker,outofbits/tracker,hoheinzollern/tracker,hoheinzollern/tracker,outofbits/tracker,hoheinzollern/tracker,hoheinzollern/tracker,hoheinzollern/tracker,outofbits/tracker,outofbits/tracker,outofbits/tracker,outofbits/tracker