Remove HDF5FILL control flag, take 2 (fixes #539)

[cwardgar]

This is identical to #542 except that it is on a branch of the upstream repo, not my personal repo. So, others can work on it.

@DennisHeimbigner this commit broke 2 tests in :dap4 and I don't feel comfortable fixing them. Can you take a look?

[cwardgar]

I did a Jenkins run just to make sure that this doesn't break any other tests: https://jenkins-aws.unidata.ucar.edu/job/cwardgar/21/

4 new failures since last run. I suspect that only dap4.test.TestServlet.testServlet and dap4.test.TestServletConstraints.testServletConstraints are related.

Gotta love the mental exercise of concluding: "oh, those other 2 failures don't count because they're just part of those tests that fail at random sometimes".

[DennisHeimbigner]

Gotta love the mental exercise of concluding: "oh, those other 2 failures don't count because they're
just part of those tests that fail at random sometimes
What are you talking about?

[cwardgar]

ucar.nc2.dt.grid.TestReadAndCountDods.readAndCount and thredds.server.ncss.controller.grid.GridAsPointDataTest.shouldGetData also failed since the last Jenkins run, but they're likely unrelated. They don't count because they often fail, either at random or because of variable external resources.

[DennisHeimbigner]

ok, I have fixed the dap4 tests