Fix children not showing in UI

https://www.pivotaltracker.com/story/show/80575150

awoods, osmandin: this line needs to change: https://github.com/fcrepo4/fcrepo4/blob/master/fcrepo-http-api/src/main/resources/views/common-metadata.vsl#L13
Please look into what it would take to keep this "count" functionality in.