PDFBOX-1969: fix JPEGFactory bug

git-svn-id: https://svn.apache.org/repos/asf/pdfbox/trunk@1577734 13f79535-47bb-0310-9956-ffa450edef68
PDFBOX-1969: activate second JPEGFactory test

git-svn-id: https://svn.apache.org/repos/asf/pdfbox/trunk@1577735 13f79535-47bb-0310-9956-ffa450edef68