opentracing -> opencensus (#802)

* update vendor directory, add go.opencensus.io

* update imports

* oops

* s/opentracing/opencensus/ & remove prometheus / zipkin stuff & remove old stats

* the dep train rides again

* fix gin build

* deps from last guy

* start in on the agent metrics

* she builds

* remove tags for now, cardinality error is fussing. subscribe instead of register

* update to patched version of opencensus to proceed for now TODO switch to a release

* meh

fix imports

* println debug the bad boys

* lace it with the tags

* update deps again

* fix all inconsistent cardinality errors

* add our own logger

* fix init

* fix oom measure

* remove bugged removal code

* fix s3 measures

* fix prom handler nil

vendor/github.com/lib/pq/.travis.yml

@@ -1,7 +1,6 @@
 language: go
 
 go:
-  - 1.5.x
   - 1.6.x
   - 1.7.x
   - 1.8.x

vendor/github.com/lib/pq/notify.go

@@ -637,7 +637,7 @@ func (l *Listener) disconnectCleanup() error {
 // after the connection has been established.
 func (l *Listener) resync(cn *ListenerConn, notificationChan <-chan *Notification) error {
 	doneChan := make(chan error)
-	go func() {
+	go func(notificationChan <-chan *Notification) {
 		for channel := range l.channels {
 			// If we got a response, return that error to our caller as it's
 			// going to be more descriptive than cn.Err().
@@ -658,7 +658,7 @@ func (l *Listener) resync(cn *ListenerConn, notificationChan <-chan *Notificatio
 			}
 		}
 		doneChan <- nil
-	}()
+	}(notificationChan)
 
 	// Ignore notifications while synchronization is going on to avoid
 	// deadlocks.  We have to send a nil notification over Notify anyway as