In certain specific cases it might be beneficial to be able to control
the metadata caching of storage image format drivers of a hypervisor.
Introduce XML machinery to set the maximum size of the metadata cache
which will be used by qemu's qcow2 driver.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
