[chromedriver] Fix typo in android chromedriver buildbot script.

TBR=navabi@chromium.org
BUG=None
TEST=None
NOTRY=True

Review URL: https://chromiumcodereview.appspot.com/24198012

git-svn-id: http://src.chromium.org/svn/trunk/src/build@224485 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

android/buildbot/bb_device_steps.py

@@ -150,7 +150,7 @@ def RunChromeDriverTests(options):
             constants.PACKAGE_INFO['chrome_stable'].package,
             constants.PACKAGE_INFO['chrome_beta'].package),
           '--revision=%s' % _GetRevision(options),
-          '--update_log'])
+          '--update-log'])
 
 def InstallApk(options, test, print_step=False):
   """Install an apk to all phones.