[Android][telemetry] Update pylib imports for modules that moved into devil.

build/android/generate_emma_html.py

 #!/usr/bin/env python
 
 # Copyright 2013 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.
 
 """Aggregates EMMA coverage files to produce html output."""
 
 import fnmatch
 import json
 import optparse
 import os
 import sys
 
-from pylib import cmd_helper
+from devil.utils import cmd_helper
 from pylib import constants
 
 
 def _GetFilesWithExt(root_dir, ext):
   """Gets all files with a given extension.
 
   Args:
     root_dir: Directory in which to search for files.
     ext: Extension to look for (including dot)
 
@@ skipping 55 matching lines @@
 
   if options.cleanup:
     for f in coverage_files:
       os.remove(f)
 
   return exit_code
 
 
 if __name__ == '__main__':
   sys.exit(main())