minor: fixing readability in the startup script for replica set integration testing

My reaction when I first saw this code and tried to read through it was something like this...

![huh](https://f.cloud.github.com/assets/489331/1195943/72056948-24a0-11e3-80f4-1928439d8bd5.jpg)

My head still hurts, but I *think* its a little more readable now. Feedback welcome.