Vendor update with github.com/ugorji/go and github.com/apache/thrift pinning (#1805)

This fix is an vendor update. Both ugorji and thrift have to be pinned
to compile. The ugorji is from etcd and thrift is from zipkin.

This fix fixes #1802.

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

vendor/github.com/aws/aws-sdk-go/internal/sdkio/io_go1.6.go

@@ -0,0 +1,10 @@
+// +build !go1.7
+
+package sdkio
+
+// Copy of Go 1.7 io package's Seeker constants.
+const (
+	SeekStart   = 0 // seek relative to the origin of the file
+	SeekCurrent = 1 // seek relative to the current offset
+	SeekEnd     = 2 // seek relative to the end
+)

vendor/github.com/aws/aws-sdk-go/internal/sdkio/io_go1.7.go

@@ -0,0 +1,12 @@
+// +build go1.7
+
+package sdkio
+
+import "io"
+
+// Alias for Go 1.7 io package Seeker constants
+const (
+	SeekStart   = io.SeekStart   // seek relative to the origin of the file
+	SeekCurrent = io.SeekCurrent // seek relative to the current offset
+	SeekEnd     = io.SeekEnd     // seek relative to the end
+)