MB-6998: remove heavy logs which block stats request from UI
MB-6998: remove heavy logs which block stats request from UI

In previous fixes we logged msgs from couchdb, which turns out to
be a flooding of msgs for bucket replicator to dump. Consequently
he bucket replicator is too busy to repond to UI stats request and
causes UI stat unaccessible.

Change-Id: Ib8155a43d0411254cc9f19e05fe510168eea2fa0
Reviewed-on: http://review.couchbase.org/21932
Reviewed-by: Junyi Xie <cec9b1c9f34a8d92cba938f3f3364d5120580782@gmail.com>
Tested-by: Junyi Xie <cec9b1c9f34a8d92cba938f3f3364d5120580782@gmail.com>

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