Replaced all instances of 'python' with 'python2'

On systems where 'python' refers to python3, redo
failed to launch. All invocations of python have been
made explicitly python2 invocations. All tests pass
on an Arch Linux system as of this commit.

redo-always.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python2
 import sys, os
 import vars, state
 from log import err