PDFBOX-370: Website build does not work with Java 6
PDFBOX-370: Website build does not work with Java 6

Work around the issue by disabling sitemap validation

git-svn-id: 73746072a361c8027bb2177f17128911b05b2bab@686646 13f79535-47bb-0310-9956-ffa450edef68

torakiki/sambox,ZhenyaM/veraPDF-pdfbox,veraPDF/veraPDF-pdfbox,joansmith/pdfbox,joansmith/pdfbox,BezrukovM/veraPDF-pdfbox,ZhenyaM/veraPDF-pdfbox,torakiki/sambox,mdamt/pdfbox,gavanx/pdflearn,veraPDF/veraPDF-pdfbox,benmccann/pdfbox,ChunghwaTelecom/pdfbox,mdamt/pdfbox,gavanx/pdflearn,mathieufortin01/pdfbox,mathieufortin01/pdfbox,BezrukovM/veraPDF-pdfbox,ChunghwaTelecom/pdfbox,benmccann/pdfbox