setup-sensu-docker could use user-defined path

[wakaru44]

Hi:

I don't really like the fact that the setup-sensu-docker.sh uses /usr/local to store its things. I would like to be able to leave all that stuff in a directory inside the working folder, or somewhere else.

So this issue is a feature request to allow the user to define a custom path.

I'll probably work on the feature myself and submit you a pull request, but I would like to have your feedback about it.

[wakaru44]

The script that you can download from http://sensuapp.org/docs/0.23/files/sensu_ssl_tool.tar seems to be using relative paths