Fixed drop action in DefaultP4Interpreter

Change-Id: Ie490c71472581232b24bacf391f0c23ed6ef0a81
diff --git a/drivers/p4runtime/src/main/java/org/onosproject/drivers/p4runtime/DefaultP4Interpreter.java b/drivers/p4runtime/src/main/java/org/onosproject/drivers/p4runtime/DefaultP4Interpreter.java
index 85167eb..6029590 100644
--- a/drivers/p4runtime/src/main/java/org/onosproject/drivers/p4runtime/DefaultP4Interpreter.java
+++ b/drivers/p4runtime/src/main/java/org/onosproject/drivers/p4runtime/DefaultP4Interpreter.java
@@ -76,7 +76,7 @@
     public static final String TABLE0 = "table0";
     public static final String SEND_TO_CPU = "send_to_cpu";
     public static final String PORT = "port";
-    public static final String DROP = "drop";
+    public static final String DROP = "_drop";
     public static final String SET_EGRESS_PORT = "set_egress_port";
     public static final String EGRESS_PORT = "egress_port";
     public static final String INGRESS_PORT = "ingress_port";