Fixes issue with client shutting down before transactions are pulled

The client the store copy method needs to perform full store copies over
 the network was closed by the RemoteStoreCopier before the transactions
 were pulled over in their entirety from the master. That can lead, in the
 presence of high transaction data volume, CCE to be thrown while doing
 full store backups. This commit fixes this issue by introducing an
 explicit done() method for the StoreCopyRequester that closes
 the client at an appropriate time.
RemoteStoreCopierTest is properly altered to check for the correct call
 sequence.
Removes some System.out.println calls that were added for monitoring
 purposes.
Cleanup: Response is Autocloseable, requester closes in a finally
Merge pull request #2176 from digitalstain/2.0-backup-fix

Fixes issue with client shutting down before transactions are pulled