Implicitly the query depth is limited by the length of the QAPI schema
query, but 'alternate' and 'array' QAPI meta-types don't consume a part
of the query string thus a loop on such types would get our traversal
code stuck in an infinite loop. Prevent this from happening by limiting
the nesting depth to 1000.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NDaniel P. Berrangé <berrange@redhat.com>