Added suggestions by Christa

Christa suggested to indicate that machines bought in the CERN Stores have not been tested for Linux compatibility by the Linux Support Team and therefore problems related to standard "Personal" CERN PC hardware purchased at CERN stores is not meant to get any Linux Support.Re__Linux_Support__only_for_CentOS_RHEL_issues_affecting_Servers_or_Managed_Desktops.eml