$ sudo rpm -e --nodeps libvirt-client
/sbin/ldconfig: relative path `0' used to build cache
warning: %postun(libvirt-client-0.10.2.2-2.fc18.x86_64) scriptlet failed, exit status 1

Some info here:
http://en.opensuse.org/openSUSE:Packaging_scriptlet_snippets

Fix is:

diff --git a/libvirt.spec b/libvirt.spec
index ccf1d97..f9ff5f3 100644
--- a/libvirt.spec
+++ b/libvirt.spec
@@ -1588,8 +1588,9 @@ 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