java_gen: delete HashFunc interface

only used internally in floodlight and not needed here
diff --git a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/HashFunc.java b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/HashFunc.java
deleted file mode 100644
index f7648d7..0000000
--- a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/HashFunc.java
+++ /dev/null
@@ -1,14 +0,0 @@
-package org.projectfloodlight.openflow.types;
-
-/** A hash function that can hash a {@link PrimitiveSinkable}.
- *
- * @author Andreas Wundsam <andreas.wundsam@bigswitch.com>
- * @param <H> - the hash.
- */
-public interface HashFunc<H extends HashValue<H>> {
-    /** Hash the PrimitivateSinkable with this hash function and return the result */
-    public H hash(PrimitiveSinkable v);
-
-    /** Provide a defined null-hash */
-    public H nullHash();
-}
\ No newline at end of file