py2.7compat: a few more files requiring print_function

tools/odrive/dfu.py

@@ -3,6 +3,7 @@
 Tool for flashing .hex files to the ODrive via the STM built-in USB DFU mode.
 """
 
+from __future__ import print_function
 import argparse
 import sys
 import time

tools/odrive/tests.py

@@ -1,4 +1,4 @@
-
+from __future__ import print_function
 import subprocess
 import shlex
 import math