Move the try/catch block deeper

src/core.js

@@ -398,17 +398,17 @@ var PDFDocument = (function PDFDocumentClosure() {
     get linearization() {
       var length = this.stream.length;
       var linearization = false;
-      try {
       if (length) {
+        try {
           linearization = new Linearization(this.stream);
           if (linearization.length != length)
             linearization = false;
-        }
         } catch (err) {
           warn('since pdf is broken pdf.js is trying to recover it ' +
                'by indexing the object; ' +
                'the error in firebug shall have a different origin');
         }
+      }
       // shadow the prototype getter with a data property
       return shadow(this, 'linearization', linearization);
     },