Fix parsing of incorrect bytes in 'extradata' for 'rows event' (julien-duponchelle#469)

Author: Chungeun Choi

pymysqlreplication/row_event.py

@@ -63,7 +63,7 @@ def __init__(self, from_packet, event_size, table_map, ctl_connection, **kwargs)
 
                     # ndb information
                     if self.extra_data_type == 0:
-                        self.nbd_info_length, self.nbd_info_format = struct.unpack('<BB', self.packet.read(1))
+                        self.nbd_info_length, self.nbd_info_format = struct.unpack('<BB', self.packet.read(2))
                         self.nbd_info = self.packet.read(self.nbd_info_length - 2)
                     # partition information
                     elif self.extra_data_type == 1: