fix error prone compiler it

git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1513080 13f79535-47bb-0310-9956-ffa450edef68
ignore .java-version file

git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1513081 13f79535-47bb-0310-9956-ffa450edef68