Drop --retry-connrefused curl flag
Drop --retry-connrefused curl flag

It was added in 7.52.0, a relatively new version (7.47.0 is currently pre-installed on Travis workers)

fniephaus/filetreeCI,fniephaus/filetreeCI,hpi-swa/filetreeCI,hpi-swa/filetreeCI,hpi-swa/smalltalkCI,fniephaus/filetreeCI,hpi-swa/smalltalkCI,hpi-swa/filetreeCI