Comment out boot cucumber tests

This is in response to the slowness noticed over the last few days and unrelated changes causing travis failures. For example:

https://github.com/rapid7/metasploit-framework/pull/4252#issuecomment-64923343

## Verification

- [x] See that this PR does not include the 30-60 minute cucumber boot tests, such as the ones on https://travis-ci.org/rapid7/metasploit-framework/builds/42627993
- [x] See that this PR is green.

/cc @lsanchez-r7 @limhoff-r7