Update prometheus client and go-metrics

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

vendor/github.com/prometheus/common/model/metric.go

@@ -44,7 +44,7 @@ func (m Metric) Before(o Metric) bool {
 
 // Clone returns a copy of the Metric.
 func (m Metric) Clone() Metric {
-	clone := Metric{}
+	clone := make(Metric, len(m))
 	for k, v := range m {
 		clone[k] = v
 	}

vendor/github.com/prometheus/common/model/time.go

@@ -163,9 +163,21 @@ func (t *Time) UnmarshalJSON(b []byte) error {
 // This type should not propagate beyond the scope of input/output processing.
 type Duration time.Duration
 
+// Set implements pflag/flag.Value
+func (d *Duration) Set(s string) error {
+	var err error
+	*d, err = ParseDuration(s)
+	return err
+}
+
+// Type implements pflag.Value
+func (d *Duration) Type() string {
+	return "duration"
+}
+
 var durationRE = regexp.MustCompile("^([0-9]+)(y|w|d|h|m|s|ms)$")
 
-// StringToDuration parses a string into a time.Duration, assuming that a year
+// ParseDuration parses a string into a time.Duration, assuming that a year
 // always has 365d, a week always has 7d, and a day always has 24h.
 func ParseDuration(durationStr string) (Duration, error) {
 	matches := durationRE.FindStringSubmatch(durationStr)
@@ -202,6 +214,9 @@ func (d Duration) String() string {
 		ms   = int64(time.Duration(d) / time.Millisecond)
 		unit = "ms"
 	)
+	if ms == 0 {
+		return "0s"
+	}
 	factors := map[string]int64{
 		"y":  1000 * 60 * 60 * 24 * 365,
 		"w":  1000 * 60 * 60 * 24 * 7,

vendor/github.com/prometheus/common/model/value.go

@@ -129,11 +129,8 @@ func (s *Sample) Equal(o *Sample) bool {
 	if !s.Timestamp.Equal(o.Timestamp) {
 		return false
 	}
-	if s.Value.Equal(o.Value) {
-		return false
-	}
 
-	return true
+	return s.Value.Equal(o.Value)
 }
 
 func (s Sample) String() string {