[autotest] Remove leftover servo references from autoupdate_EndToEndTest.

This test used to feature a bunch of references to servo. This work was
removed but there are a few things left over in the test.

I will remove them now to make the test easier to follow.

More details in CL:302542 and CL:302871

BUG=chromium:709710
TEST=test_that <ip> autoupdate_EndToEndTest

Change-Id: I97cde59286335017715a9be779bd1a8c43205210
Reviewed-on: https://chromium-review.googlesource.com/540187
Commit-Ready: David Haddock <dhaddock@chromium.org>
Tested-by: David Haddock <dhaddock@chromium.org>
Reviewed-by: Don Garrett <dgarrett@chromium.org>
diff --git a/server/site_tests/autoupdate_EndToEndTest/autoupdate_EndToEndTest.py b/server/site_tests/autoupdate_EndToEndTest/autoupdate_EndToEndTest.py
index 3535500..ba3fc4a 100755
--- a/server/site_tests/autoupdate_EndToEndTest/autoupdate_EndToEndTest.py
+++ b/server/site_tests/autoupdate_EndToEndTest/autoupdate_EndToEndTest.py
@@ -30,9 +30,6 @@
 class ExpectedUpdateEventChainFailed(error.TestFail):
     """Raised if we fail to receive an expected event in a chain."""
 
-class RequiredArgumentMissing(error.TestError):
-    """Raised if the test is missing a required argument."""
-
 
 # Update event types.
 EVENT_TYPE_DOWNLOAD_COMPLETE = '1'
@@ -1618,14 +1615,11 @@
         logging.info('Update successful, test completed')
 
 
-    # TODO(garnold) Remove the use_servo argument once control files on all
-    # release branches have caught up.
-    def run_once(self, host, test_conf, use_servo=False):
+    def run_once(self, host, test_conf):
         """Performs a complete auto update test.
 
         @param host: a host object representing the DUT
         @param test_conf: a dictionary containing test configuration values
-        @param use_servo: DEPRECATED
 
         @raise error.TestError if anything went wrong with setting up the test;
                error.TestFail if any part of the test has failed.