delete old copies of vbucket after vbucket movemenet
delete old copies of vbucket after vbucket movemenet

So that memory is freed earlier.

After config update, we're doing sync on config replication first to
play extra safe. And then we're deleting vbucket on old nodes.

Change-Id: I15693d791a781dfcf0c523fb2bb6f5d4e6c01ed2
Reviewed-on: http://review.couchbase.org/14195
Reviewed-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>
Tested-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>

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