autoupdate_EndToEnd: Don't install forwarding rules upon Brillo reboot.

We do this already right before we trigger an update. This reduces
reboot_device() into a simple delegate to host.reboot(), although it
makes sense to keep it in the TestPlatform API regardless.

BUG=b:24158510
TEST=Reverse forwarding installed only once after a reboot.

Change-Id: I10f2f2168363d7129929564963c8372a34c5953c
Reviewed-on: https://chromium-review.googlesource.com/304606
Commit-Ready: Gilad Arnold <garnold@chromium.org>
Tested-by: Gilad Arnold <garnold@chromium.org>
Reviewed-by: Simran Basi <sbasi@chromium.org>
diff --git a/server/site_tests/autoupdate_EndToEndTest/autoupdate_EndToEndTest.py b/server/site_tests/autoupdate_EndToEndTest/autoupdate_EndToEndTest.py
index 50f53fa..ed68431 100755
--- a/server/site_tests/autoupdate_EndToEndTest/autoupdate_EndToEndTest.py
+++ b/server/site_tests/autoupdate_EndToEndTest/autoupdate_EndToEndTest.py
@@ -1227,7 +1227,6 @@
 
     def reboot_device(self):
         self._host.reboot()
-        self._install_forwarding()
 
 
     def prep_artifacts(self, test_conf):