[FAB-1374] Remove bd_counter sample client

https://jira.hyperledger.org/browse/FAB-1374

I wrote this while developing the Kafka orderer for testing. The existing
sample clients (broadcast_timestamp and deliver_stdout) provide the same
functionality and in a more modular, Unix-like way. Keeping the
bd_counter around just increases maintenance burden.

Change-Id: Ibc98ff9744b42ecd23cf1076002e8b8dd604a899
Signed-off-by: Kostas Christidis <[email protected]>

Author: kchristidis