HttpClientConnectionOperator should use HttpHost.getAddress if available

In HttpClientConnectionOperator Instead of:

final InetAddress[] addresses = this.dnsResolver.resolve(host.getHostName());

Use:
InetAddress explicit = target.getAddress();
final InetAddress[] addresses = explicit!=null ? new InetAddress[]

: this.dnsResolver.resolve(host.getHostName());

e.g. On a host with round-robin dns (mulitple A or AAAA records) I wish to connect to a specific server rather than trying multiple hosts.