Variable name consistency should be check and fixed

In several places of the code "FAIclass" is used to design the FAI profile. FAIclass should only be used for what it is in the LDAP : the list for FAI profiles, space separated, followed by ":" and then the FAI release.

At least class_workstationStartup should be fixed.

(from redmine: issue id 717, created on 2012-03-22, closed on 2012-12-20)