Refining driver subsystem to facilitate coordinated start-up.

- for ONOS-6402

Change-Id: I7f64fc62ad1d451fcf55624b2422b60631a3c8e8
diff --git a/core/api/src/main/java/org/onosproject/net/driver/DriverAdminService.java b/core/api/src/main/java/org/onosproject/net/driver/DriverAdminService.java
index f9f2532..12edfbc 100644
--- a/core/api/src/main/java/org/onosproject/net/driver/DriverAdminService.java
+++ b/core/api/src/main/java/org/onosproject/net/driver/DriverAdminService.java
@@ -20,7 +20,8 @@
 /**
  * Service for managing drivers and driver behaviour implementations.
  */
-public interface DriverAdminService extends DriverService, BehaviourClassResolver {
+public interface DriverAdminService
+        extends DriverRegistry, BehaviourClassResolver {
 
     /**
      * Returns the set of driver providers currently registered.