Modify the metric "Info" to "Gauge"

This commit fixes the bug encountered while feeding data to
scraping tools.
- Openmetric keyword "Info" is not compatible with general
scraping tools. Alternative is to use "Gauge" for displaying
device information.

Test Plan:
PASSED: Metrics consumed properly by a scraping tool without
        any error.
PASSED: Validate necessary information is being displayed with
        new metric type Gauge.
PASSED: API Test

Story: 2010918
Task: 50117

Change-Id: I57ed6ac379aeee56ea4469fd561777d335ede32e
Signed-off-by: Aman Pandae <AmanPandae.Mothukuri@windriver.com>

metrics-exporter-api/docker/metrics-exporter-api/openmet_handler.go

@@ -122,7 +122,7 @@ func convertToOpnMetFormat(pfd PfDevices, p VfpodInfo) string {
 // Function to cast PfDevice data from struct to openmetrics format
 func devStatOpenMet(devInfo PfDevice) string {
 	var reg = openmetrics.NewRegistry()
-	regName := "network_interface_device"
+	regName := "network_interface_device_info"
 
 	// OpenMetrics Not showing Fields if it is empty
 	// so adding a Blank string to show alias
@@ -144,7 +144,7 @@ func devStatOpenMet(devInfo PfDevice) string {
 		alias,
 		devInfo.OperState,
 		devInfo.Pciaddr,
-	)
+	).Add(float64(1))
 
 	// convert all netlink.LinkStatistics Struct to map
 	fields := reflect.TypeOf(*devInfo.Statistics)
@@ -182,9 +182,9 @@ func devStatOpenMet(devInfo PfDevice) string {
 // for Network Interface Device Info
 func regDevInfo(
 	reg *openmetrics.Registry, name string, help string, labels []string,
-) openmetrics.InfoFamily {
+) openmetrics.GaugeFamily {
 
-	var deviceInfo = reg.Info(openmetrics.Desc{
+	var deviceInfo = reg.Gauge(openmetrics.Desc{
 		Name:   name,
 		Help:   help,
 		Labels: labels,