feature #4111: Explicit reutrn nil if user not selected
feature #4111: Explicit reutrn nil if user not selected

(cherry picked from commit bac205df9ba46e87aaff21393c10b7e744afafcc)

baby-gnu/one,hsanjuan/one,hsanjuan/one,alvarosimon/one,hsanjuan/one,unistra/one,atodorov-storpool/one,unistra/one,alvarosimon/one,juanmont/one,hsanjuan/one,atodorov-storpool/one,ohamada/one,juanmont/one,goberle/one,juanmont/one,ohamada/one,juanmont/one,abelCoronado93/one,atodorov-storpool/one,abelCoronado93/one,alvarosimon/one,atodorov-storpool/one,alvarosimon/one,baby-gnu/one,abelCoronado93/one,OpenNebula/one,atodorov-storpool/one,baby-gnu/one,juanmont/one,juanmont/one,OpenNebula/one,alvarosimon/one,atodorov-storpool/one,OpenNebula/one,ohamada/one,hsanjuan/one,OpenNebula/one,goberle/one,alvarosimon/one,ohamada/one,baby-gnu/one,goberle/one,baby-gnu/one,abelCoronado93/one,baby-gnu/one,ohamada/one,unistra/one,hsanjuan/one,ohamada/one,atodorov-storpool/one,hsanjuan/one,unistra/one,atodorov-storpool/one,unistra/one,hsanjuan/one,unistra/one,abelCoronado93/one,baby-gnu/one,juanmont/one,unistra/one,goberle/one,unistra/one,juanmont/one,OpenNebula/one,goberle/one,goberle/one,OpenNebula/one,OpenNebula/one,alvarosimon/one,alvarosimon/one,baby-gnu/one,OpenNebula/one,ohamada/one,abelCoronado93/one,juanmont/one,abelCoronado93/one,ohamada/one,OpenNebula/one,goberle/one,abelCoronado93/one,goberle/one,atodorov-storpool/one