Avoid need for sleeps after creating channel using API

The end-to-end test suite currently contains arbitrary sleeps to give the network time to become stable before completing chaincode lifecycle deployment. These sleeps only appear to be required when the channel is created using the admin API. When the channel is created using the test-network scripts, chaincode deployment seems to work without sleeps.

Maybe it would be good to either:

1. Have the channel commands (perhaps optionally) check completion of configuration before returning so the system is in a fully usable state immediately after creation completes; or
2. Extend the channel API to allow client code to check for a stable system state.