Add tenant isolation to the swift tests

This commit adds tenant isolation to the swift api tests. This should
prevent a race condition between the different test classes when
running in parallel.

part of blueprint speed-up-tempest

Change-Id: I8d59dad3df1afff43b1b3485d2d8c30a081dadd7
diff --git a/etc/tempest.conf.sample b/etc/tempest.conf.sample
index f1aaa07..9788533 100644
--- a/etc/tempest.conf.sample
+++ b/etc/tempest.conf.sample
@@ -272,6 +272,9 @@
 # Set to True if the Account Quota middleware is enabled
 accounts_quotas_available = True
 
+# Set operator role for tests that require creating a container
+operator_role = Member
+
 [boto]
 # This section contains configuration options used when executing tests
 # with boto.