Add possibility to disable running stadium projects tests

This patch adds possibility to disable running of tests related to:
* networking-bgpvpn,
* neutron-fwaas,
* networking-sfc

which were moved to neutron-tempest-plugin repo recently.
This will be useful when tests will be run for one of
stable branches up to Stein, in which those tests are still
in project's repo.

Change-Id: I61dc252920154e7e0998eb2c7c1f026814796cdf
diff --git a/neutron_tempest_plugin/bgpvpn/base.py b/neutron_tempest_plugin/bgpvpn/base.py
index aeecbfc..b436a5d 100644
--- a/neutron_tempest_plugin/bgpvpn/base.py
+++ b/neutron_tempest_plugin/bgpvpn/base.py
@@ -72,8 +72,13 @@
     @classmethod
     def skip_checks(cls):
         super(BaseBgpvpnTest, cls).skip_checks()
+        msg = None
         if not utils.is_extension_enabled('bgpvpn', 'network'):
             msg = "Bgpvpn extension not enabled."
+        elif not CONF.bgpvpn.run_bgpvpn_tests:
+            msg = ("Running of bgpvpn related tests is disabled in "
+                   "plugin configuration.")
+        if msg:
             raise cls.skipException(msg)
 
     def create_bgpvpn(self, client, **kwargs):