TUN-5010: --region should be a string flag

origin/supervisor.go

@@ -74,7 +74,7 @@ func NewSupervisor(config *TunnelConfig, reconnectCh chan ReconnectSignal, grace
 	if len(config.EdgeAddrs) > 0 {
 		edgeIPs, err = edgediscovery.StaticEdge(config.Log, config.EdgeAddrs)
 	} else {
-		edgeIPs, err = edgediscovery.ResolveEdge(config.Log, "")
+		edgeIPs, err = edgediscovery.ResolveEdge(config.Log, config.Region)
 	}
 	if err != nil {
 		return nil, err

origin/tunnel.go

@@ -45,6 +45,7 @@ type TunnelConfig struct {
 	ClientID         string
 	CloseConnOnce    *sync.Once // Used to close connectedSignal no more than once
 	EdgeAddrs        []string
+	Region           string
 	HAConnections    int
 	IncidentLookup   IncidentLookup
 	IsAutoupdated    bool