Wake up the connection notifier iff it is in sleep state.

Change-Id: Ibd2579aeaa456fb14904b27ca00e453c56d33786
Reviewed-on: http://review.couchbase.org/39251
Reviewed-by: Michael Wiederhold <mike@couchbase.com>
Tested-by: Chiyoung Seo <chiyoung@couchbase.com>