**/*.py: use /usr/bin/env to find python

src/trusted/validator_mips/dgen/dgen_opt.py

-#!/usr/bin/python
+#!/usr/bin/env python
 #
 # Copyright 2012 The Native Client Authors.  All rights reserved.
 # Use of this source code is governed by a BSD-style license that can
 # be found in the LICENSE file.
 # Copyright 2012, Google Inc.
 #
 
 """
 Table minimization algorithm.
 """
@@ skipping 55 matching lines @@
         for r in rows:
             if not used[col]:
                 del r.patterns[col]
 
 
 def each_index_pair(sequence):
     """Utility function: Generates each unique index pair in sequence."""
     for i in range(0, len(sequence)):
         for j in range(i + 1, len(sequence)):
             yield (i, j)