Correctly handle applyOps command as part of role graph updating

Currently when an applyOps op is processed by logOp(), the following error is logged:
ERROR: Unsupported modification to roles collection in oplog; TODO how to remedy. OplogOperationUnsupported Unsupported oplog operation Oplog entry: c

Instead, the behavior needs to be that the role graph system parses the command and responds to anything that changes role data.