Correct DWG mimetype to match IANA registration

git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/HEAD/root@20625 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261

source/java/org/alfresco/repo/content/metadata/DWGMetadataExtracter.java

@@ -65,6 +65,7 @@ public class DWGMetadataExtracter extends AbstractMappingMetadataExtracter
     public static String[] SUPPORTED_MIMETYPES = new String[] {
             MimetypeMap.MIMETYPE_APP_DWG,
             MimetypeMap.MIMETYPE_IMG_DWG,
+            "image/x-dwg", // Was used before IANA registration
     };
     
     public DWGMetadataExtracter()