qemu: tpm: Remove TPM state after successful migration

qemu: tpm: Remove TPM state after successful migration

This patch 'fixes' the behavior of the persistent_state TPM domain XML
attribute that intends to preserve the state of the TPM but should not
keep the state around on all the hosts a VM has been migrated to. It
removes the TPM state directory structure from the source host upon
successful migration when non-shared storage is used. Similarly, it
removes it from the destination host upon migration failure when
non-shared storage is used.

Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>