api: Implement bucket notification. (#2271)

* Implement basic S3 notifications through queues

Supports multiple queues and three basic queue types:

1. NilQueue -- messages don't get sent anywhere
2. LogQueue -- messages get logged
3. AmqpQueue -- messages are sent to an AMQP queue

* api: Implement bucket notification.

Supports two different queue types

- AMQP
- ElasticSearch.

* Add support for redis

vendor/github.com/streadway/amqp/fuzz.go

@@ -0,0 +1,16 @@
+// +build gofuzz
+package amqp
+
+import "bytes"
+
+func Fuzz(data []byte) int {
+	r := reader{bytes.NewReader(data)}
+	frame, err := r.ReadFrame()
+	if err != nil {
+		if frame != nil {
+			panic("frame is not nil")
+		}
+		return 0
+	}
+	return 1
+}