Add nodes_wanted() variant that takes config as a parameter.
Add nodes_wanted() variant that takes config as a parameter.

Change-Id: I3085f46fb077e85e395e10ea66b3d640d4f1a81f
Reviewed-on: http://review.couchbase.org/35290
Reviewed-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>
Tested-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>

mschoch/ns_server,mschoch/ns_server,nimishzynga/ns_server,daverigby/ns_server,t3rm1n4l/ns_server,membase/ns_server,ceejatec/ns_server,t3rm1n4l/ns_server,ceejatec/ns_server,nimishzynga/ns_server,membase/ns_server,mschoch/ns_server,membase/ns_server,membase/ns_server,nimishzynga/ns_server,ceejatec/ns_server,nimishzynga/ns_server,daverigby/ns_server,ceejatec/ns_server,daverigby/ns_server,t3rm1n4l/ns_server,mschoch/ns_server,membase/ns_server,t3rm1n4l/ns_server,mschoch/ns_server,membase/ns_server,ceejatec/ns_server,mschoch/ns_server,daverigby/ns_server,nimishzynga/ns_server,nimishzynga/ns_server,t3rm1n4l/ns_server,ceejatec/ns_server,daverigby/ns_server