Fix typo in systemtap tapset directory name

The systemtap directory for tapsets is called

  /usr/share/systemtap/tapset

Not

 /usr/share/systemtap/tapsets

* daemon/Makefile.am,libvirt.spec.in: s/tapsets/tapset/

daemon/Makefile.am

@@ -165,7 +165,7 @@ nodist_libvirtd_SOURCES = probes.h
 
 BUILT_SOURCES += probes.h
 
-tapsetdir = $(datadir)/systemtap/tapsets
+tapsetdir = $(datadir)/systemtap/tapset
 tapset_DATA = libvirtd.stp
 
 probes.h: probes.d

libvirt.spec.in

@@ -898,7 +898,7 @@ fi
 %config(noreplace) %{_sysconfdir}/sysconfig/libvirtd
 %config(noreplace) %{_sysconfdir}/libvirt/libvirtd.conf
 %if %{with_dtrace}
-%{_datadir}/systemtap/tapsets/libvirtd.stp
+%{_datadir}/systemtap/tapset/libvirtd.stp
 %endif
 %dir %attr(0700, root, root) %{_localstatedir}/log/libvirt/qemu/
 %dir %attr(0700, root, root) %{_localstatedir}/log/libvirt/lxc/