Rollback state if cloning container fails part way
Rollback state if cloning container fails part way

Wrap the entire container clone process in an exception handling
block which deletes the (partially created) new container on
error. Also sanity check if the target container exists before
attempting to clone.

Signed-off-by: Daniel P. Berrange <bb938cf255e055ff3507f2627d214e8e62118fcf@redhat.com>

libvirt/libvirt-sandbox,libvirt/libvirt-sandbox,erenyagdiran/libvirt-sandbox,gczarcinski/libvirt-sandbox,gczarcinski/libvirt-sandbox,gczarcinski/libvirt-sandbox,agx/libvirt-sandbox-debian,agx/libvirt-sandbox-debian,gczarcinski/libvirt-sandbox,agx/libvirt-sandbox-debian,erenyagdiran/libvirt-sandbox,libvirt/libvirt-sandbox,gczarcinski/libvirt-sandbox,gczarcinski/libvirt-sandbox,erenyagdiran/libvirt-sandbox,agx/libvirt-sandbox-debian,erenyagdiran/libvirt-sandbox,agx/libvirt-sandbox-debian