Adjust ManagedLedger.md to new interface
Problem: interface should look like https://gist.github.com/brnbrnrd/3c2c5475b9d7a0d5a2e2021d9aed255e
Solution: fix, reupload the contract.
Problem: interface should look like https://gist.github.com/brnbrnrd/3c2c5475b9d7a0d5a2e2021d9aed255e
Solution: fix, reupload the contract.