Gossip/discovery: add String() to NetworkMember

This commit simply adds a String() method to NetworkMember,
because otherwise- the struct is printed without its field names
and it's hard to figure out which refers to what.

Change-Id: I5ea6552b79afa21b3222ebe1b7b22349851b653a
Signed-off-by: Yacov Manevich <yacovm@il.ibm.com>

gossip/discovery/discovery.go

@@ -17,6 +17,8 @@ limitations under the License.
 package discovery
 
 import (
+	"fmt"
+
 	"github.com/hyperledger/fabric/gossip/common"
 	proto "github.com/hyperledger/fabric/protos/gossip"
 )
@@ -80,6 +82,11 @@ type NetworkMember struct {
 	InternalEndpoint string
 }
 
+// String returns a string representation of the NetworkMember
+func (n *NetworkMember) String() string {
+	return fmt.Sprintf("Endpoint: %s, InternalEndpoint: %s, PKI-ID: %v, Metadata: %v", n.Endpoint, n.InternalEndpoint, n.PKIid, n.Metadata)
+}
+
 // PreferredEndpoint computes the endpoint to connect to,
 // while preferring internal endpoint over the standard
 // endpoint