Fixed Compound Metric Configuration acceptance test. Closes issue #128.

Signed-off-by:Beatriz Rezener <beatrizrezener@gmail.com>
Hello,
The "@compound_metric_configuration" is a object created by the Factory Girl, but the "My Compound Metric" isn't. So, I think I couldn't use the same text parameter.
I tried make it more generic, what you think? If you have any ideas just let me know.