[telemetry] Update examples so they work.

tools/telemetry/examples/telemetry_perf_test.py

 #!/usr/bin/env python
 # Copyright (c) 2012 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.
+
 import os
 import sys
 import time
 
-sys.path.append(os.path.join(os.path.dirname(__file__), '..'))
+sys.path.append(os.path.join(os.path.dirname(__file__), os.pardir))
 
 from telemetry.core import browser_finder
 from telemetry.core import browser_options
 
+
 def Main(args):
   options = browser_options.BrowserFinderOptions()
   parser = options.CreateParser('telemetry_perf_test.py')
   options, args = parser.parse_args(args)
 
   browser_to_create = browser_finder.FindBrowser(options)
   assert browser_to_create
   with browser_to_create.Create() as b:
     tab = b.tabs[0]
 
     # Measure round-trip-time for evaluate
     times = []
     for i in range(1000):
       start = time.time()
       tab.EvaluateJavaScript('%i * 2' % i)
       times.append(time.time() - start)
     N = float(len(times))
     avg = sum(times, 0.0) / N
     squared_diffs = [(t - avg) * (t - avg) for t in times]
     stdev = sum(squared_diffs, 0.0) / (N - 1)
     times.sort()
     percentile_75 = times[int(0.75 * N)]
 
     print "%s: avg=%f; stdev=%f; min=%f; 75th percentile = %f" % (
       "Round trip time (seconds)",
       avg, stdev, min(times), percentile_75)
 
   return 0
 
+
 if __name__ == '__main__':
   sys.exit(Main(sys.argv[1:]))