check_system: improve RHCS support message and version comparison
check_system: improve RHCS support message and version comparison

"red hat storage" -> "red hat ceph storage"

"RHEL 7.1" -> "RHEL 7"

and make the version number check verify the very latest version

https://bugzilla.redhat.com/show_bug.cgi?id=1354059

WingkaiHo/ceph-ansible,ceph/ceph-ansible,travmi/ceph-ansible,jtaleric/ceph-ansible,fgal/ceph-ansible,travmi/ceph-ansible,WingkaiHo/ceph-ansible,ceph/ceph-ansible,albertomurillo/ceph-ansible,jtaleric/ceph-ansible,font/ceph-ansible,fgal/ceph-ansible,bengland2/ceph-ansible,font/ceph-ansible,albertomurillo/ceph-ansible,albertomurillo/ceph-ansible,bengland2/ceph-ansible,WingkaiHo/ceph-ansible