java_gen: enable generation for all messages, lots of related fixes
diff --git a/java_gen/templates/_imports.java b/java_gen/templates/_imports.java
index bac7065..5b86571 100644
--- a/java_gen/templates/_imports.java
+++ b/java_gen/templates/_imports.java
@@ -7,6 +7,7 @@
 import org.openflow.protocol.instruction.*;
 import org.openflow.protocol.match.*;
 import org.openflow.protocol.oxm.*;
+import org.openflow.protocol.queueprop.*;
 import org.openflow.types.*;
 import org.openflow.types.*;
 import org.openflow.util.*;