spec: don't use chkconfig --list

https://bugzilla.redhat.com/show_bug.cgi?id=694403 reports that
the specfile is incorrectly checking for a running libvirt-guests
service.  For example,

$ LC_ALL=es_ES chkconfig --list libvirt-guests
libvirt-guests 	  0:desactivado		 1:desactivado	   2:desactivado     3:activo	 4:activo  5:activo	    6:desactivado

will fail to find 5:on, even though it is active.  But chkconfig
already has a mode where you can silently use the exit status to
check for an active service.

* libvirt.spec.in (%post): Use simpler chkconfig options, to avoid
issues with localization.

libvirt.spec.in

@@ -874,8 +874,7 @@ getent passwd qemu >/dev/null || \
 # We want to install the default network for initial RPM installs
 # or on the first upgrade from a non-network aware libvirt only.
 # We check this by looking to see if the daemon is already installed
-/sbin/chkconfig --list libvirtd 1>/dev/null 2>&1
-if test $? != 0 && test ! -f %{_sysconfdir}/libvirt/qemu/networks/default.xml
+if ! /sbin/chkconfig libvirtd && test ! -f %{_sysconfdir}/libvirt/qemu/networks/default.xml
 then
     UUID=`/usr/bin/uuidgen`
     sed -e "s,</name>,</name>\n  <uuid>$UUID</uuid>," \
@@ -1008,8 +1007,7 @@ fi
 /sbin/chkconfig --add libvirt-guests
 if [ $1 -ge 1 ]; then
     level=$(/sbin/runlevel | /bin/cut -d ' ' -f 2)
-    if /sbin/chkconfig --list libvirt-guests 2>/dev/null \
-        | /bin/grep -q $level:on ; then
+    if /sbin/chkconfig --levels $level libvirt-guests; then
         # this doesn't do anything but allowing for libvirt-guests to be
         # stopped on the first shutdown
         /sbin/service libvirt-guests start > /dev/null 2>&1 || true