tests: move pool to /var/lib/libvirt to avoid selinux warnings
tests: move pool to /var/lib/libvirt to avoid selinux warnings

With the current path in the journal there were warnings:
libvirtd: cannot lookup default selinux label for /mnt/tmpPool/vmTmpDestination.qcow2

cockpituous/cockpit,moraleslazaro/cockpit,mvollmer/cockpit,cockpit-project/cockpit,garrett/cockpit,deryni/cockpit,moraleslazaro/cockpit,moraleslazaro/cockpit,deryni/cockpit,cockpituous/cockpit,moraleslazaro/cockpit,martinpitt/cockpit,deryni/cockpit,martinpitt/cockpit,moraleslazaro/cockpit,garrett/cockpit,garrett/cockpit,mvollmer/cockpit,moraleslazaro/cockpit,cockpit-project/cockpit,garrett/cockpit,garrett/cockpit,cockpituous/cockpit,martinpitt/cockpit,cockpit-project/cockpit,cockpit-project/cockpit,cockpituous/cockpit,mvollmer/cockpit,deryni/cockpit,mvollmer/cockpit,moraleslazaro/cockpit,deryni/cockpit,cockpituous/cockpit,martinpitt/cockpit,deryni/cockpit,cockpituous/cockpit,deryni/cockpit,martinpitt/cockpit,cockpit-project/cockpit,mvollmer/cockpit