Early jumps to the cleanup label caused a crash of the libvirt_lxc
container helper as the cleanup section called
virLXCControllerDeleteInterfaces(ctrl) without checking the ctrl argument
for NULL. The argument was de-referenced soon after.

$ /usr/libexec/libvirt_lxc
/usr/libexec/libvirt_lxc: missing --name argument for configuration
Segmentation fault