prevents the "begin now" link from showing at the same time as the "begin reservation" link

Ran into the attached problem while looking at PR #101. This fixes it. If you can switch an instrument you shouldn't see the "Begin now" link.

![screen shot 2014-03-03 at 11 53 54 am](https://f.cloud.github.com/assets/569564/2313436/9190f600-a309-11e3-81a7-381d6436ae1a.png)