java_gen/pom.xml: adapt to extended floodlight-buildinfo format

introduced in bigswitch/floodlight@4d8e3e38d31
Merge into master from pull request #240:
Use aux id java type for of controller connection message (https://github.com/floodlight/loxigen/pull/240)
Merge into master from pull request #241:
java_gen/pom.xml: adapt to extended floodlight-buildinfo format (https://github.com/floodlight/loxigen/pull/241)