autoupdate_StartOOBEUpdate: Use nebraska.py instead of nano_omaha_devserver.py

This CL changes this autotest to use nebraska.py for the update process.
This is only for the cellular tests.

We are moving away from the use cases of nano_omaha_devserver.py and
eventually will deprecate it.

BUG=chromium:999047
TEST=test_that 100.90.30.183 autoupdate_NonBlockingOOBEUpdate.delta --args="running_at_desk=True job_repo_url=http://100.115.168.196:8082/static/reef-release/R81-12860.0.0/autotest/packages"
TEST=test_that 100.90.30.183 autoupdate_ForcedOOBEUpdate.cellular.full
--args="running_at_desk=True
job_repo_url=http://100.115.168.196:8082/static/reef-release/R81-12860.0.0/autotest/packages"
// For this since I didn't have a cellular enabled device, I commented
out the part that setups the celluar and the test went fine working with nebraska.

Change-Id: I09d0785e7127c7d341ccc30104be676f18647e87
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/autotest/+/2031493
Tested-by: Amin Hassani <ahassani@chromium.org>
Commit-Queue: Amin Hassani <ahassani@chromium.org>
Reviewed-by: David Haddock <dhaddock@chromium.org>
diff --git a/server/site_tests/autoupdate_ForcedOOBEUpdate/autoupdate_ForcedOOBEUpdate.py b/server/site_tests/autoupdate_ForcedOOBEUpdate/autoupdate_ForcedOOBEUpdate.py
index 561a2d1..43cb028 100644
--- a/server/site_tests/autoupdate_ForcedOOBEUpdate/autoupdate_ForcedOOBEUpdate.py
+++ b/server/site_tests/autoupdate_ForcedOOBEUpdate/autoupdate_ForcedOOBEUpdate.py
@@ -93,19 +93,11 @@
         payload_info = None
         if cellular:
             self._change_cellular_setting_in_update_engine(True)
-            # Get the payload's information (size, SHA256 etc) since we will be
-            # setting up our own omaha instance on the DUT. We pass this to
-            # the client test.
-            payload = self._get_payload_url(full_payload=full_payload)
-            staged_url, _ = self._stage_payload_by_uri(payload)
-            payload_info = self._get_staged_file_info(staged_url)
 
         # Call client test to start the forced OOBE update.
         self._run_client_test_and_check_result('autoupdate_StartOOBEUpdate',
                                                image_url=update_url,
-                                               cellular=cellular,
-                                               payload_info=payload_info,
-                                               full_payload=full_payload)
+                                               cellular=cellular)
 
         if interrupt is not None:
             # Choose a random downloaded progress to interrupt the update.