matrix: Switch to the nio http client.

main.py

@@ -386,8 +386,8 @@ def room_close_cb(data, buffer):
 def matrix_unload_cb():
     matrix_config_free(matrix.globals.CONFIG)
 
-    for server in SERVERS.values():
-        server.store_olm()
+    # for server in SERVERS.values():
+    #     server.store_olm()
 
     W.prnt("", "unloading")
     return W.WEECHAT_RC_OK

matrix/server.py

@@ -329,7 +329,7 @@ class MatrixServer:
 
         self.send_buffer = b""
         self.current_message = None
-        self.reset_parser()
+        self.client.disconnect()
 
         self.lag = 0
         W.bar_item_update("lag")