Fix python scripts in src/tools/

tools/valgrind/drmemory_analyze.py

-#!/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.
 
 # drmemory_analyze.py
 
 ''' Given a Dr. Memory output file, parses errors and uniques them.'''
 
 import logging
 import optparse
@@ skipping 84 matching lines @@
       for report_list in self.reports:
         report = ''
         for line in report_list:
           report += str(line)
         logging.error('\n' + report)
       logging.error("Total: %i error reports" % len(self.reports))
       return -1
     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"
                     "(used to normalize source paths in baseline)")
 
   (options, args) = parser.parse_args()
   if len(args) == 0:
     parser.error("no filename specified")
   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())