fix mobile get pac file error

1. Change listen ip to 0.0.0.0
2. Mobile can't fetch pac file and CA file without forward_local

Author: xyuanmu

pythonlib/local/proxy_handler.py

@@ -107,7 +107,7 @@ def forward_local(self):
             out_list.append(("%s: %s\r\n" % (key, value)).encode('iso-8859-1'))
         out_list.append(b"\r\n")
         out_list.append(content)
-        self.wfile.write(b"".join(out_list))
+        if content: self.wfile.write(b"".join(out_list))
 
     def do_METHOD(self):
         touch_active()
@@ -130,6 +130,10 @@ def do_METHOD(self):
         if host.startswith("127.0.0.1") or host.startswith("localhost"):
             return self.forward_local()
 
+        if host_ip == config.get_listen_ip():
+            xlog.info("Browse localhost by proxy")
+            return self.forward_local()
+
         self.parsed_url = urllib.parse.urlparse(self.path)
 
         if host in config.HOSTS_GAE: