Melusine: Proper cupsFilter alternatives

ppd/gen-melusine-xcpt

@@ -20,8 +20,7 @@ set('Throughput', 35);
 set('TTRasterizer', 'Type42');
 set('Protocols', 'PJL BCP TBCP');
 
-set('cupsFilter', 'application/vnd.cups-pdf 0 xerox-xcpt');
-set('cupsFilter', 'application/vnd.cups-postscript 0 xerox-xcpt');
+set('cupsFilter', ['application/vnd.cups-pdf 0 xerox-xcpt', 'application/vnd.cups-postscript 0 xerox-xcpt']);
 
 set('ColorDevice', 1);
 set('DefaultColorSpace', 'CMYK');