MB-7398 Rename added node to what was specified as its address.
MB-7398 Rename added node to what was specified as its address.

As part of information that is posted to engageCluster2 we provide a
requestedTargetNodeHostname field that indicates how the node was
referred in the cluster. So target node can rename itself to use this
hostname.

Change-Id: I72e6c06b5c61834abecdaaf52a820924f87018d5
Reviewed-on: http://review.couchbase.org/25341
Reviewed-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>
Tested-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>

nimishzynga/ns_server,vzasade/ns_server,membase/ns_server,mschoch/ns_server,nimishzynga/ns_server,mschoch/ns_server,nimishzynga/ns_server,vzasade/ns_server,pavel-blagodov/ns_server,mschoch/ns_server,ceejatec/ns_server,daverigby/ns_server,pavel-blagodov/ns_server,nimishzynga/ns_server,ceejatec/ns_server,mschoch/ns_server,ceejatec/ns_server,t3rm1n4l/ns_server,membase/ns_server,ceejatec/ns_server,ceejatec/ns_server,ceejatec/ns_server,mschoch/ns_server,daverigby/ns_server,vzasade/ns_server,t3rm1n4l/ns_server,pavel-blagodov/ns_server,nimishzynga/ns_server,t3rm1n4l/ns_server,daverigby/ns_server,daverigby/ns_server,daverigby/ns_server,pavel-blagodov/ns_server,t3rm1n4l/ns_server,nimishzynga/ns_server,membase/ns_server,membase/ns_server,vzasade/ns_server,mschoch/ns_server,membase/ns_server,t3rm1n4l/ns_server,membase/ns_server