ext.auth: return nil instead of OkConnect

This allows falling through to a next `ConnectHandler` is authentication succeeds making if easier to combine with other `ConnectHandler`s.

ext/auth/basic.go

@@ -68,7 +68,7 @@ func BasicConnect(realm string, f func(user, passwd string) bool) goproxy.HttpsH
 			ctx.Resp = BasicUnauthorized(ctx.Req, realm)
 			return goproxy.RejectConnect, host
 		}
-		return goproxy.OkConnect, host
+		return nil, host
 	})
 }