Fix function call that breaks vimside on mac

After running `:call vimside#StartEnsime()`, I got the error in the image below.. Traced it to a missing bracket :smile: 

![Screen Shot 2013-01-10 at 23 50 09](https://f.cloud.github.com/assets/648684/58759/8086b614-5b80-11e2-9597-ff547931fcbe.png)

First pull request of the year :dancer: