Move test decorators to common

services and extension decorators are based on CONF and needed by
Tempest only, so moving them to tempest.common.
Since a few plugnis use them today, use debtcollector to avoid
breaking all dependencies.

Change-Id: Ibd52153d00b8e60fb8c89e38d94e358ddc787251
diff --git a/tempest/api/network/admin/test_quotas.py b/tempest/api/network/admin/test_quotas.py
index aa8b2dc..f69d7c5 100644
--- a/tempest/api/network/admin/test_quotas.py
+++ b/tempest/api/network/admin/test_quotas.py
@@ -14,10 +14,10 @@
 #    under the License.
 
 from tempest.api.network import base
+from tempest.common import utils
 from tempest.lib.common.utils import data_utils
 from tempest.lib.common.utils import test_utils
 from tempest.lib import decorators
-from tempest import test
 
 
 class QuotasTest(base.BaseAdminNetworkTest):
@@ -38,7 +38,7 @@
     @classmethod
     def skip_checks(cls):
         super(QuotasTest, cls).skip_checks()
-        if not test.is_extension_enabled('quotas', 'network'):
+        if not utils.is_extension_enabled('quotas', 'network'):
             msg = "quotas extension not enabled."
             raise cls.skipException(msg)