Move proxy consts into init file

mtglib/network/init.go

 	DefaultDNSTimeout  = time.Second
 	DefaultHTTPTimeout = DefaultTimeout
 	DefaultBufferSize  = 4096
+
+	ProxyDialerOpenThreshold        = 5
+	ProxyDialerHalfOpenTimeout      = time.Minute
+	ProxyDialerResetFailuresTimeout = 10 * time.Second
 )
 
 var (

mtglib/network/proxy_dialer.go

 	"time"
 )
 
-const (
-	ProxyDialerOpenThreshold        = 5
-	ProxyDialerHalfOpenTimeout      = time.Minute
-	ProxyDialerResetFailuresTimeout = 10 * time.Second
-)
-
 func newProxyDialer(baseDialer Dialer, proxyURL *url.URL) Dialer {
 	params := proxyURL.Query()