Use util provided to get chromeos version.

No need to have our own function.

BUG=chromium:1081031
TEST=oobe, interrupt

Change-Id: Iaa6a96943db59f876b6601b51cd156efc63c108a
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/autotest/+/2223573
Tested-by: David Haddock <dhaddock@chromium.org>
Reviewed-by: Amin Hassani <ahassani@chromium.org>
Commit-Queue: David Haddock <dhaddock@chromium.org>
diff --git a/server/cros/update_engine/update_engine_test.py b/server/cros/update_engine/update_engine_test.py
index b43240f..a41416f 100644
--- a/server/cros/update_engine/update_engine_test.py
+++ b/server/cros/update_engine/update_engine_test.py
@@ -14,7 +14,6 @@
 from xml.etree import ElementTree
 
 from autotest_lib.client.common_lib import error
-from autotest_lib.client.common_lib import lsbrelease_utils
 from autotest_lib.client.common_lib import utils
 from autotest_lib.client.common_lib.cros import dev_server
 from autotest_lib.client.cros.update_engine import update_engine_event as uee
@@ -350,12 +349,6 @@
         return new_gs_url.replace('gs://', 'https://storage.googleapis.com/')
 
 
-    def _get_chromeos_version(self):
-        """Read the ChromeOS version from /etc/lsb-release."""
-        lsb = self._host.run('cat /etc/lsb-release').stdout
-        return lsbrelease_utils.get_chromeos_release_version(lsb)
-
-
     def _suspend_then_resume(self):
         """Suspends and resumes the host DUT."""
         try:
diff --git a/server/site_tests/autoupdate_ForcedOOBEUpdate/autoupdate_ForcedOOBEUpdate.py b/server/site_tests/autoupdate_ForcedOOBEUpdate/autoupdate_ForcedOOBEUpdate.py
index 8f8e675..05ebc2f 100644
--- a/server/site_tests/autoupdate_ForcedOOBEUpdate/autoupdate_ForcedOOBEUpdate.py
+++ b/server/site_tests/autoupdate_ForcedOOBEUpdate/autoupdate_ForcedOOBEUpdate.py
@@ -120,7 +120,7 @@
                                                   full_payload=full_payload,
                                                   public=cellular,
                                                   moblab=moblab)
-        before = self._get_chromeos_version()
+        before = self._host.get_release_version()
         payload_info = None
         if cellular:
             self._change_cellular_setting_in_update_engine(True)
@@ -188,5 +188,5 @@
             inactive,
             'The active image slot did not change after the update.',
             self._host)
-        after = self._get_chromeos_version()
+        after = self._host.get_release_version()
         logging.info('Successfully force updated from %s to %s.', before, after)
diff --git a/server/site_tests/autoupdate_Interruptions/autoupdate_Interruptions.py b/server/site_tests/autoupdate_Interruptions/autoupdate_Interruptions.py
index 99c582b..6e05336 100644
--- a/server/site_tests/autoupdate_Interruptions/autoupdate_Interruptions.py
+++ b/server/site_tests/autoupdate_Interruptions/autoupdate_Interruptions.py
@@ -40,7 +40,7 @@
 
         update_url = self.get_update_url_for_test(job_repo_url,
                                                   full_payload=full_payload)
-        chromeos_version = self._get_chromeos_version()
+        chromeos_version = self._host.get_release_version()
         active, inactive = kernel_utils.get_kernel_state(self._host)
         # Choose a random downloaded progress to interrupt the update.
         progress = random.uniform(0.1, 0.6)