java/OFMatchV3Ver13: bugfix for MatchFieldIterator
MatchFieldIterator would return match fields for which the
prerequisites were not met. Then the get() method for those
MatchFields would return null (hiding the fields).
This bug fix makes iterator() behave consistently with
get() / getMasked()
diff --git a/java_gen/templates/_imports.java b/java_gen/templates/_imports.java
index 0c95916..dde3ac0 100644
--- a/java_gen/templates/_imports.java
+++ b/java_gen/templates/_imports.java
@@ -26,6 +26,7 @@
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Sets;
+import com.google.common.collect.AbstractIterator;
import com.google.common.collect.UnmodifiableIterator;
import com.google.common.hash.Funnel;
import com.google.common.hash.PrimitiveSink;