Fix python scripts in src/tools/

tools/valgrind/drmemory_analyze.py

Index: tools/valgrind/drmemory_analyze.py
diff --git a/tools/valgrind/drmemory_analyze.py b/tools/valgrind/drmemory_analyze.py
index a7e9d5ec1b482aa55321c2d6719ec6a548fbcbaf..b33ff76090b187c75bdee3899472ae993e3f6240 100755
--- a/tools/valgrind/drmemory_analyze.py
+++ b/tools/valgrind/drmemory_analyze.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.
@@ -103,9 +103,9 @@ class DrMemoryAnalyze:
     logging.info("PASS: No error reports found")
     return 0
 
-if __name__ == '__main__':
+
+def main():
   '''For testing only. The DrMemoryAnalyze class should be imported instead.'''
-  retcode = 0
   parser = optparse.OptionParser("usage: %prog [options] <files to analyze>")
   parser.add_option("", "--source_dir",
                     help="path to top of source tree for this build"
@@ -117,6 +117,8 @@ if __name__ == '__main__':
   filenames = args
 
   analyzer = DrMemoryAnalyze(options.source_dir, filenames)
-  retcode = analyzer.Report(False)
+  return analyzer.Report(False)
 
-  sys.exit(retcode)
+
+if __name__ == '__main__':
+  sys.exit(main())