Since we're adding a 'commitQuorum' field to the createIndexes command to enable simultaneous index builds, we need to explore whether we should assert/warn/ignore if the 'commitQuorum' field is also present when running the createIndexes command in standalone mode. Similarly, how the setIndexCommitQuorum command should behave on a standalone node.

UPDATE: we've settled on error'ing on receipt of commitQuorum settings on standalones.

Note: internally we can set whatever we want, this is just defining the user interface.