build: use python2 for messages_map.py

.travis.yml

@@ -11,7 +11,6 @@ addons:
       - protobuf-compiler
       - libprotobuf-dev
       - python-protobuf
-      - python3-protobuf
 
 env:
   global:

Dockerfile

@@ -9,4 +9,4 @@ RUN apt-get update
 # install build tools and dependencies
 
 RUN apt-get install -y build-essential git python python-ecdsa gcc-arm-none-eabi
-RUN apt-get install -y protobuf-compiler libprotobuf-dev python-protobuf python3-protobuf
+RUN apt-get install -y protobuf-compiler libprotobuf-dev python-protobuf

firmware/protob/.gitignore

@@ -2,5 +2,6 @@
 *_pb2.py
 *.pb.c
 *.pb.h
+*.pyc
 messages_map.h
 __pycache__/

firmware/protob/messages_map.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python3
+#!/usr/bin/env python2
 from collections import defaultdict
 from messages_pb2 import MessageType
 from types_pb2 import wire_in, wire_out, wire_debug_in, wire_debug_out, wire_tiny, wire_bootloader