fix typos in documentation

Change-Id: Ib35eda5520456a1ecdb02c40c8e90f6f8d7f9269
diff --git a/doc/source/configuration.rst b/doc/source/configuration.rst
index ce799ad..f477a3e 100644
--- a/doc/source/configuration.rst
+++ b/doc/source/configuration.rst
@@ -21,7 +21,7 @@
 ``self.os_admin.servers_client``.
 
 Similarly, setting ``rbac_test_role`` to a non-admin role results in Tempest's
-primary credentials being overriden by the role specified by
+primary credentials being overridden by the role specified by
 ``rbac_test_role``.
 
 .. note::