Fix python scripts in src/tools/

tools/bisect-builds.py

Index: tools/bisect-builds.py
diff --git a/tools/bisect-builds.py b/tools/bisect-builds.py
index a4a3f7591133e8d5c2e1ebc2b48ea7e8a29fac0f..6a4d09ddf169a6bd0bc214c03f8a1f5c00be4b36 100755
--- a/tools/bisect-builds.py
+++ b/tools/bisect-builds.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python
 # Copyright (c) 2011 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
@@ -45,6 +45,7 @@ import urllib
 from xml.etree import ElementTree
 import zipfile
 
+
 class PathContext(object):
   """A PathContext is used to carry the information used to construct URLs and
   paths when dealing with the storage server and archives."""
@@ -267,6 +268,7 @@ def RunRevision(context, revision, zipfile, profile, args):
 
   return (subproc.returncode, stdout, stderr)
 
+
 def AskIsGoodBuild(rev, status, stdout, stderr):
   """Ask the user whether build |rev| is good or bad."""
   # Loop until we get a response that we can parse.
@@ -277,6 +279,7 @@ def AskIsGoodBuild(rev, status, stdout, stderr):
     if response and response == 'q':
       raise SystemExit()
 
+
 def Bisect(platform,
            good_rev=0,
            bad_rev=0,
@@ -534,5 +537,6 @@ def main():
   print 'Built at revision:'
   print BUILD_VIEWVC_URL % first_known_bad_rev
 
+
 if __name__ == '__main__':
   sys.exit(main())