for discussion in https://0xdata.atlassian.net/browse/HEX-1814
gets a write lock exception. Can look at the test and sandbox/commands.log and decide if  you think the h2o architecture is doing what it's designed to do, or if this is a temporal state that might go away in time, or the test is not-supported user behavior.
depends on your point of view, I think?
Merge branch 'master' of github.com:h2oai/h2o