Error message typo in jValue validation in shell's WriteConcern constructor

76  throw Error("j value must either true or false if defined, not " + opts.j);

> new WriteConcern(0, 0, null)

2014-03-27T18:54:25.907-0400 Error: j value must either true or false if defined, not null at src/mongo/shell/bulk_api.js:76