`mocha.ignoreLeaks()` did not make mocha ignore leaks at my setup, resulting in lots of tests failing, while this syntax fixes that.

`mocha.ignoreLeaks(true)` also does the job. This method was changed in Mocha (https://github.com/visionmedia/mocha/commit/d6330cb678511f371a47c95accbef93ecb092c9c)

I should have done it in a separate pull though, shall I make a new PR for the (non-template) spec related stuff and remove it from this one?