Fix/raptor worker registration #710

Job	Run time
test-getting_started / tests	2m 39s
test-tutorials (configuration.ipynb) / tests	1m 39s
test-tutorials (debugging.ipynb) / tests	2m 41s
test-tutorials (describing_tasks.ipynb) / tests	3m 45s
test-tutorials (multiple_pilots.ipynb) / tests	3m 26s
test-tutorials (profiling.ipynb) / tests	2m 31s
test-tutorials (raptor.ipynb) / tests	2m 23s
test-tutorials (raptor_mpi.ipynb) / tests	4m 2s
test-tutorials (staging_data.ipynb) / tests	2m 18s
test-tutorials (submission.ipynb) / tests	1m 38s
	27m 2s

Provide feedback