Allow tenant isolation by default

Many people running into the issue of forgetting
to allow tenant isolation when running tempest in parallel.

Since the parallel is the `default mode`, the default config
should support this use case.

Change-Id: Ia30cfbc239c8b8628ac0926424c4100d013cd620
diff --git a/etc/tempest.conf.sample b/etc/tempest.conf.sample
index bc4198f..d81d3bb 100644
--- a/etc/tempest.conf.sample
+++ b/etc/tempest.conf.sample
@@ -125,7 +125,7 @@
 # achieved configuring a list of test accounts (boolean value)
 # Deprecated group/name - [compute]/allow_tenant_isolation
 # Deprecated group/name - [orchestration]/allow_tenant_isolation
-#allow_tenant_isolation = false
+#allow_tenant_isolation = true
 
 # If set to True it enables the Accounts provider, which locks
 # credentials to allow for parallel execution with pre-provisioned
diff --git a/tempest/config.py b/tempest/config.py
index 4588b20..a66aa9b 100644
--- a/tempest/config.py
+++ b/tempest/config.py
@@ -40,7 +40,7 @@
                help="Path to the yaml file that contains the list of "
                     "credentials to use for running tests"),
     cfg.BoolOpt('allow_tenant_isolation',
-                default=False,
+                default=True,
                 help="Allows test cases to create/destroy tenants and "
                      "users. This option requires that OpenStack Identity "
                      "API admin credentials are known. If false, isolated "