Add missing license header.

git-svn-id: https://svn.apache.org/repos/asf/maven/enforcer/trunk@1626494 13f79535-47bb-0310-9956-ffa450edef68
code simplification

git-svn-id: https://svn.apache.org/repos/asf/maven/enforcer/trunk@1626496 13f79535-47bb-0310-9956-ffa450edef68
fixed code style

git-svn-id: https://svn.apache.org/repos/asf/maven/enforcer/trunk@1626497 13f79535-47bb-0310-9956-ffa450edef68