LUCENE-5322: define-lucene-javadoc-url should only be called once as part of Solr's  generate-maven-artifacts (merged trunk r1541653)

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1541654 13f79535-47bb-0310-9956-ffa450edef68