Fixes #39 - Unable to follow symlinks.

Turns out that we were naively going up a directoryon a bash script.

However, we should first find out where the bash script *really* is located,
then go up a directory and take the real directory of that to find the installation.

This is friendlier to our debian/rpm start scripts.  Thanks to @muuki88 for diagnosing
and proposing an alternative solution.
Merge pull request #45 from sbt/wip/symlinks

Fixes #39 - Unable to follow symlinks.
Merge remote-tracking branch 'origin/master' into wip/jsuereth-upstart
Fix typo and ensure that upstart configuration works.

* Typo was causing upstart script to be ignored in favor of bash.
* For some reason chdir wasn't working on my local ubuntu.  Workaround issued.