Properties with default values don't work

Describe the bug Some sensors have default properties values that apparently don't work.

How to reproduce Steps to reproduce the behavior:

Remove the default property from one of the sensors in thesonar-project.properties.
Run sonnar-scanner against the project.
sonar-scanner will generate a warning message mentioning that the property was not set.

Expected behavior The sonar-scanner analysis should work normally by setting the property to its default value.

Screenshots None.

Additional context

fsantiag / sonar-clojure