Improve sphinx program detection
Improve sphinx program detection

rpm-software-management/libdnf,rpm-software-management/libhif,rpm-software-management/libdnf,hughsie/libhif,hughsie/libhif,hughsie/libhif,rpm-software-management/libhif,rpm-software-management/libhif,hughsie/libhif,rpm-software-management/libdnf,rpm-software-management/libdnf,rpm-software-management/libhif