Many uses of qobject_from_jsonf() convert JSON objects. Create new
convenience function qdict_from_jsonf_nofail() that includes the
conversion to QDict. The next few commits will put it to use.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180703085358.13941-22-armbru@redhat.com>