[libvirt] build failure on ubuntu

I haven't looked into this closely yet, but Daniel's security refactoring broke the Ubuntu 'make check' build when apparmor is enabled: CC secaatest.o secaatest.c: In function 'main': secaatest.c:18: error: implicit declaration of function 'virSecurityDriverStartup' [-Wimplicit-function-declaration] -- Eric Blake eblake(a)redhat.com +1-801-349-2682 Libvirt virtualization library http://libvirt.org