spec: Fix script warning when uninstalling libvirt-client

https://bugzilla.redhat.com/show_bug.cgi?id=888071
(cherry picked from commit d60c7f75)

libvirt.spec.in

@@ -1575,8 +1575,9 @@ fi
 /sbin/chkconfig --add libvirt-guests
 %endif
 
-%postun client -p /sbin/ldconfig
+%postun client
 
+/sbin/ldconfig
 %if %{with_systemd}
 %if %{with_systemd_macros}
 %systemd_postun_with_restart libvirt-guests.service