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

src/trusted/validator_mips/dgen/dgen_input.py

-#!/usr/bin/python
+#!/usr/bin/env python
 # Copyright (c) 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.
 
 """
 A simple recursive-descent parser for the table file format.
 
 The grammar implemented here is roughly (taking some liberties with whitespace
 and comment parsing):
 
@@ skipping 103 matching lines @@
     _line_no += 1
     _line = _in.readline()
     if _line:
         _line = re.sub(r'#.*', '', _line).strip()
     else:
         _line = None
 
 
 def unexpected():
     raise Exception('Line %d: Unexpected line in input: %s' % (_line_no, _line))