renaming test suite

Change-Id: I4860a47acc1f3754bea5363cf92d24c55aebd860
diff --git a/setup.cfg b/setup.cfg
index 5bac445..bab1c71 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -24,7 +24,7 @@
     tempest_horizon
 [entry_points]
 tempest.test_plugins =
-    horizon_tests = tempest_horizon.plugin:HorizonTempestPlugin
+    horizon = tempest_horizon.plugin:HorizonTempestPlugin
 
 [build_sphinx]
 source-dir = doc/source