Use mattermost v5 module (#1192)

vendor/github.com/go-asn1-ber/asn1-ber/util.go

@@ -0,0 +1,24 @@
+package ber
+
+import "io"
+
+func readByte(reader io.Reader) (byte, error) {
+	bytes := make([]byte, 1, 1)
+	_, err := io.ReadFull(reader, bytes)
+	if err != nil {
+		if err == io.EOF {
+			return 0, io.ErrUnexpectedEOF
+		}
+		return 0, err
+	}
+	return bytes[0], nil
+}
+
+func isEOCPacket(p *Packet) bool {
+	return p != nil &&
+		p.Tag == TagEOC &&
+		p.ClassType == ClassUniversal &&
+		p.TagType == TypePrimitive &&
+		len(p.ByteValue) == 0 &&
+		len(p.Children) == 0
+}