Small improvement for XMP generation.

git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/trunk@1028021 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/fop/pdf/PDFMetadata.java

@@ -151,6 +151,9 @@ public class PDFMetadata extends PDFStream {
         }
         dc.addDate(info.getCreationDate());
 
+        //Somewhat redundant but some PDF/A checkers issue a warning without this.
+        dc.setFormat("application/pdf");
+
         //PDF/A identification
         PDFAMode pdfaMode = pdfDoc.getProfile().getPDFAMode();
         if (pdfaMode.isPDFA1LevelB()) {