Remove unused argument in Tempest Plugin

Remove unused argument expect_errors from create_chassis method.

Change-Id: I85448930d2b2ad7c29dcb10bdc202d03f5ab8b38
diff --git a/ironic_tempest_plugin/tests/api/admin/base.py b/ironic_tempest_plugin/tests/api/admin/base.py
index af6d283..86e4144 100644
--- a/ironic_tempest_plugin/tests/api/admin/base.py
+++ b/ironic_tempest_plugin/tests/api/admin/base.py
@@ -123,7 +123,7 @@
 
     @classmethod
     @creates('chassis')
-    def create_chassis(cls, description=None, expect_errors=False):
+    def create_chassis(cls, description=None):
         """Wrapper utility for creating test chassis.
 
         :param description: A description of the chassis. If not supplied,