Raise errors on failures in loading data

[jonrkarr]

hsload currently prints console messages when data loading fails (e.g., request entity too large):

https://github.com/HDFGroup/h5pyd/blob/aa60cf5eb7bd960504e4916f29d3176d054a6522/h5pyd/_apps/utillib.py#L532

To make errors easier to detect, it would be helpful for hsload to exit with a non-zero exit code such as by calling sys.exit(1) after L532 above.

[jreadey]

See commit: https://github.com/HDFGroup/h5pyd/commit/994cffc0399610b9c171e5ab4ee838f7ec8e5db0. new behavior is for hsload to fail on an error unless the --ignore flag is used. This is in the aggregate branch - will close issue once merged with master.

[jreadey]

Fix is in master.

[jreadey]

Closing - fix is in the 0.12.0 release on PyPI.