spec: Adjust librbd / librados dependency names

librbd1-devel and librados2-devel have their package name changed to
librbd-devel and librados-devel on all the supported Fedora versions and
CentOS / RHEL 8.

For more info about this change, please, refer to the following page:
https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html-single/considerations_in_adopting_rhel_8/indexSigned-off-by: NFabiano Fidêncio <fidencio@redhat.com>
Reviewed-by: NDaniel P. Berrangé <berrange@redhat.com>

libvirt.spec.in

@@ -335,9 +335,14 @@ BuildRequires: device-mapper-devel
 # For XFS reflink clone support
 BuildRequires: xfsprogs-devel
 %if %{with_storage_rbd}
+%if 0%{?fedora} || 0%{?rhel} > 7
+BuildRequires: librados-devel
+BuildRequires: librbd-devel
+%else
 BuildRequires: librados2-devel
 BuildRequires: librbd1-devel
 %endif
+%endif
 %if %{with_storage_gluster}
 BuildRequires: glusterfs-api-devel >= 3.4.1
 BuildRequires: glusterfs-devel >= 3.4.1