Update deps without licenses

The following packes did not have discernible LICENSE files at the hash we have
vendored:
  github.com/beorn7/perks
  github.com/daviddengcn/go-colortext
  github.com/garyburd/redigo
  github.com/prometheus/common
  github.com/shurcooL/sanitized_anchor_name
  github.com/stretchr/objx

This commit updates all of them and updates the central LICENSE file.

vendor/github.com/prometheus/common/expfmt/decode.go

@@ -37,12 +37,13 @@ type DecodeOptions struct {
 }
 
 // ResponseFormat extracts the correct format from a HTTP response header.
-func ResponseFormat(h http.Header) (Format, error) {
+// If no matching format can be found FormatUnknown is returned.
+func ResponseFormat(h http.Header) Format {
 	ct := h.Get(hdrContentType)
 
 	mediatype, params, err := mime.ParseMediaType(ct)
 	if err != nil {
-		return "", fmt.Errorf("invalid Content-Type header %q: %s", ct, err)
+		return FmtUnknown
 	}
 
 	const (
@@ -52,19 +53,19 @@ func ResponseFormat(h http.Header) (Format, error) {
 
 	switch mediatype {
 	case ProtoType:
-		if p := params["proto"]; p != ProtoProtocol {
-			return "", fmt.Errorf("unrecognized protocol message %s", p)
+		if p, ok := params["proto"]; ok && p != ProtoProtocol {
+			return FmtUnknown
 		}
-		if e := params["encoding"]; e != "delimited" {
-			return "", fmt.Errorf("unsupported encoding %s", e)
+		if e, ok := params["encoding"]; ok && e != "delimited" {
+			return FmtUnknown
 		}
-		return FmtProtoDelim, nil
+		return FmtProtoDelim
 
 	case textType:
 		if v, ok := params["version"]; ok && v != TextVersion {
-			return "", fmt.Errorf("unrecognized protocol version %s", v)
+			return FmtUnknown
 		}
-		return FmtText, nil
+		return FmtText
 
 	case jsonType:
 		var prometheusAPIVersion string
@@ -76,27 +77,26 @@ func ResponseFormat(h http.Header) (Format, error) {
 		}
 
 		switch prometheusAPIVersion {
-		case "0.0.2":
-			return FmtJSON2, nil
+		case "0.0.2", "":
+			return fmtJSON2
 		default:
-			return "", fmt.Errorf("unrecognized API version %s", prometheusAPIVersion)
+			return FmtUnknown
 		}
 	}
 
-	return "", fmt.Errorf("unsupported media type %q, expected %q or %q", mediatype, ProtoType, textType)
+	return FmtUnknown
 }
 
-// NewDecoder returns a new decoder based on the HTTP header.
-func NewDecoder(r io.Reader, format Format) (Decoder, error) {
+// NewDecoder returns a new decoder based on the given input format.
+// If the input format does not imply otherwise, a text format decoder is returned.
+func NewDecoder(r io.Reader, format Format) Decoder {
 	switch format {
 	case FmtProtoDelim:
-		return &protoDecoder{r: r}, nil
-	case FmtText:
-		return &textDecoder{r: r}, nil
-	case FmtJSON2:
-		return newJSON2Decoder(r), nil
+		return &protoDecoder{r: r}
+	case fmtJSON2:
+		return newJSON2Decoder(r)
 	}
-	return nil, fmt.Errorf("unsupported decoding format %q", format)
+	return &textDecoder{r: r}
 }
 
 // protoDecoder implements the Decoder interface for protocol buffers.
@@ -107,7 +107,29 @@ type protoDecoder struct {
 // Decode implements the Decoder interface.
 func (d *protoDecoder) Decode(v *dto.MetricFamily) error {
 	_, err := pbutil.ReadDelimited(d.r, v)
-	return err
+	if err != nil {
+		return err
+	}
+	if !model.IsValidMetricName(model.LabelValue(v.GetName())) {
+		return fmt.Errorf("invalid metric name %q", v.GetName())
+	}
+	for _, m := range v.GetMetric() {
+		if m == nil {
+			continue
+		}
+		for _, l := range m.GetLabel() {
+			if l == nil {
+				continue
+			}
+			if !model.LabelValue(l.GetValue()).IsValid() {
+				return fmt.Errorf("invalid label value %q", l.GetValue())
+			}
+			if !model.LabelName(l.GetName()).IsValid() {
+				return fmt.Errorf("invalid label name %q", l.GetName())
+			}
+		}
+	}
+	return nil
 }
 
 // textDecoder implements the Decoder interface for the text protcol.
@@ -129,13 +151,14 @@ func (d *textDecoder) Decode(v *dto.MetricFamily) error {
 		if len(fams) == 0 {
 			return io.EOF
 		}
+		d.fams = make([]*dto.MetricFamily, 0, len(fams))
 		for _, f := range fams {
 			d.fams = append(d.fams, f)
 		}
 	}
 
-	*v = *d.fams[len(d.fams)-1]
-	d.fams = d.fams[:len(d.fams)-1]
+	*v = *d.fams[0]
+	d.fams = d.fams[1:]
 
 	return nil
 }