zip: fix another typo in zip64.

Author: ctalkington

lib/archivers/zip/zip-archive-output-stream.js

@@ -244,7 +244,7 @@ ZipArchiveOutputStream.prototype._writeCentralDirectoryZip64 = function() {
   this.write(zipUtil.getEightBytes(this._archive.centralOffset + this._archive.centralLength));
 
   // total number of disks
-  this.write(this.getLongBytes(1));
+  this.write(zipUtil.getLongBytes(1));
 };
 
 ZipArchiveOutputStream.prototype._writeCentralFileHeader = function(ae) {