CBD-220: switched ns_server_sup to supervisor2
CBD-220: switched ns_server_sup to supervisor2

So that we don't have to rely on supervisor_cushion for compaction
daemon.

Change-Id: I1199636cbf1142a4742423120b443ae7cec09de9
Reviewed-on: http://review.couchbase.org/25429
Reviewed-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>
Tested-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>

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