Fix incorrect exception catch in host cleanup.

In cleanup error.AutoservRunError was being caught to check whether or not
the 'restart ui' pathway on a DUT was successful. This was a typoe and should have
been error.AutotestRunError.

BUG=None
TEST=Ran cleanup on a host that is currently down in the lab and watched it reboot.

Change-Id: I036fe8f6293fadc49c66a430ebe3813a8c4f7f66
Reviewed-on: https://gerrit.chromium.org/gerrit/42508
Reviewed-by: Scott Zawalski <scottz@chromium.org>
Tested-by: Scott Zawalski <scottz@chromium.org>
diff --git a/server/hosts/site_host.py b/server/hosts/site_host.py
index bfe6cc3..fd8c448 100644
--- a/server/hosts/site_host.py
+++ b/server/hosts/site_host.py
@@ -366,7 +366,7 @@
             self.run('restart ui')
             client_at.run_static_method('autotest_lib.client.cros.cros_ui',
                                         '_wait_for_login_prompt')
-        except error.AutoservRunError:
+        except error.AutotestRunError:
             logging.warn('Unable to restart ui, rebooting device.')
             # Since restarting the UI fails fall back to normal Autotest
             # cleanup routines, i.e. reboot the machine.