Fix for JIRA ONOS-4620. Whenever networkconfiguration is deleted even the queued will be removed

Change-Id: I8d7f1a873af90cf86ea34f1a2b1585ef4c3e46e4
diff --git a/core/api/src/main/java/org/onosproject/net/config/NetworkConfigService.java b/core/api/src/main/java/org/onosproject/net/config/NetworkConfigService.java
index 064272f..d1d280f 100644
--- a/core/api/src/main/java/org/onosproject/net/config/NetworkConfigService.java
+++ b/core/api/src/main/java/org/onosproject/net/config/NetworkConfigService.java
@@ -177,4 +177,19 @@
      * @param <S>               type of subject
      */
     <S> void removeConfig(String subjectClassKey, S subject, String configKey);
+
+    /**
+     * Clears the  configuration including queued based on the subject.
+     * If does not exists this call has no effect.
+     *
+     * @param subject           configuration subject
+     */
+    <S> void removeConfig(S subject);
+
+    /**
+     * Clears the complete configuration including queued.
+     * If does not exists this call has no effect.
+     *
+     */
+    <S> void removeConfig();
 }