Improve selenium RC failure message.

tools/testing/run_selenium.py

 #!/usr/bin/python
 
 # Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 #
 
 """Script to actually open a browser and perform the test, and reports back with
 the result. It uses Selenium WebDriver when possible for running the tests. It
 uses Selenium RC for Safari.
@@ skipping 117 matching lines @@
   if args.executable and args.browser != 'dartium':
     print 'Executable path only supported when browser=dartium.'
     sys.exit(1)
   return args.out, args.browser, args.executable, args.timeout, args.mode
 
 def print_server_error():
   """Provide the user an informative error message if we attempt to connect to
   the Selenium remote control server, but cannot access it. Then exit the
   program."""
   print ('ERROR: Could not connect to Selenium RC server. Are you running'
-      ' java -jar selenium-server-standalone-*.jar? If not, start '
-      'it before running this test.')
+      ' java -jar tools/testing/selenium-server-standalone-*.jar? If not, '
+      'start it before running this test.')
   sys.exit(1)
 
 def start_browser(browser, executable_path, html_out):
   if browser == 'chrome':
     # Note: you need ChromeDriver *in your path* to run Chrome, in addition to
     # installing Chrome. Also note that the build bot runs have a different path
     # from a normal user -- check the build logs.
     return selenium.webdriver.Chrome()
   elif browser == 'dartium':
     script_dir = os.path.dirname(os.path.abspath(__file__))
@@ skipping 179 matching lines @@
   browser = start_browser(browser_name, executable_path, html_out)
 
   try:
     output = run_test_in_browser(browser, html_out, timeout, mode)
     return report_results(mode, output)
   finally:
     close_browser(browser)
 
 if __name__ == "__main__":
   sys.exit(main(sys.argv))