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.
java_gen/pom.xml: Bump version to 0.4.0

Snapshotting/freezing 0.3.8 for fl2 platform release.
Merge into master from pull request #312:
java_gen/pom.xml: Bump version to 0.4.0 (https://github.com/floodlight/loxigen/pull/312)
IPv6Address: remove redundant null assignment
Merge into master from pull request #309:
java: discard the IPv6 zone id when parsing addresses (https://github.com/floodlight/loxigen/pull/309)
openflow_input: add TLVs for NAT gentable
Merge into master from pull request #313:
openflow_input: add TLVs for NAT gentable (https://github.com/floodlight/loxigen/pull/313)
Merge branch 'master' of github.com:alshabib/loxigen into of14-pr