Update PatientSetQueryBuilderService.groovy

The facts containing the concept_cd 'SECURITY' should never be retreived (Patient set can contain patient from other nodes if not expluded). I do not know if this is the best place to put it, but I hope you will have a better idea. Another aproache would be to have some sort of EXCLUDE constraint which, than, would allow us to move the constraint into the JS file for subset query.
Merge pull request #3 from fguitton/patch-2

Do select patients based on security concepts.