exit with reason stopped if rebalance is stopped
exit with reason stopped if rebalance is stopped

Not just stop as we did while running pre-rebalance janitor.

Change-Id: I46010b77501df1a9504481d75035b41094375835
Reviewed-on: http://review.couchbase.org/39693
Tested-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>
Reviewed-by: Aliaksey Artamonau <3c875bcfb3adf2a65b2ae7686ca921e6c9433147@gmail.com>

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