Cannot get mongo fixture to work with mongo 3.6

[bmoscon]

I cannot get the server fixture working with mongodb 3.6 on ubuntu. It works perfectly with 3.4, but not 3.6. I'm using it in conjunction with Arctic. The fixture just waits forever for the server to come up (I only waited a few minutes before killing it).

[eeaston]

The command-line flags have probably changed again :/ I'll see what CircleCI is using and try and get a more recent mongo version in the tests