Fixing drivers & providers Buck app builds

Change-Id: I6a02a68568037eca0a0b82ad4f83ff18bfeada5f
diff --git a/drivers/ovsdb/BUCK b/drivers/ovsdb/BUCK
index 336d4b0..6015611 100644
--- a/drivers/ovsdb/BUCK
+++ b/drivers/ovsdb/BUCK
@@ -23,4 +23,5 @@
     category = 'Drivers',
     url = 'http://onosproject.org',
     description = 'ONOS OVSDB Device Drivers application.',
+    required_apps = [ 'org.onosproject.ovsdb' ],
 )