Bump AWS SDK

Fixes https://github.com/docker/distribution/issues/3097

Signed-off-by: Yong Wen Chua <lawliet89@users.noreply.github.com>

vendor/github.com/aws/aws-sdk-go/internal/sdkrand/read.go

@@ -0,0 +1,11 @@
+// +build go1.6
+
+package sdkrand
+
+import "math/rand"
+
+// Read provides the stub for math.Rand.Read method support for go version's
+// 1.6 and greater.
+func Read(r *rand.Rand, p []byte) (int, error) {
+	return r.Read(p)
+}

vendor/github.com/aws/aws-sdk-go/internal/sdkrand/read_1_5.go

@@ -0,0 +1,24 @@
+// +build !go1.6
+
+package sdkrand
+
+import "math/rand"
+
+// Read backfills Go 1.6's math.Rand.Reader for Go 1.5
+func Read(r *rand.Rand, p []byte) (n int, err error) {
+	// Copy of Go standard libraries math package's read function not added to
+	// standard library until Go 1.6.
+	var pos int8
+	var val int64
+	for n = 0; n < len(p); n++ {
+		if pos == 0 {
+			val = r.Int63()
+			pos = 7
+		}
+		p[n] = byte(val)
+		val >>= 8
+		pos--
+	}
+
+	return n, err
+}