java: discard the IPv6 zone id when parsing addresses

Zone IDs are used in link-local addresses to specify the interface name or
number (RFC 4007). The InetSocketAddress class includes a zone id in the output
of getHostString() for link-local addresses. This change ignores the zone id
instead of raising an exception.
diff --git a/java_gen/pre-written/src/test/java/org/projectfloodlight/openflow/types/IPv6AddressTest.java b/java_gen/pre-written/src/test/java/org/projectfloodlight/openflow/types/IPv6AddressTest.java
index a397c2a..fd26856 100644
--- a/java_gen/pre-written/src/test/java/org/projectfloodlight/openflow/types/IPv6AddressTest.java
+++ b/java_gen/pre-written/src/test/java/org/projectfloodlight/openflow/types/IPv6AddressTest.java
@@ -399,4 +399,10 @@
             assertNotNull(e.getMessage());
         }
     }
+
+    @Test
+    public void testZoneId() throws OFParseError {
+        assertEquals("::", IPv6Address.of("::%eth0").toString(true, false));
+        assertEquals("1:0:0:4::8", IPv6Address.of("1:0:0:4:0:0:0:8%2").toString(true, false));
+    }
 }