'show devices diff' or 'pull diff' doen't work in case of 'default format cli'

[v1shnya]

Setting default format cli I'm getting a nasty error trying to achieve the base product functionality

nobody@controller> show devices diff
Oct 24 11:48:27.120278: compare_device_config_type: 1797: XML error: Get configuration: application operation-failed Format not supported
CLI command error

At the same time show compare function has an xml extension that makes it working.

Looking at the code if I would say I suggest to modify rpc_datastore_diff func in clixon-controller/src/controller_rpc.c just to replace unsupported formats with supported

clixon-controller/src/controller_rpc.c

Line 2803 in 82557dc

if (format != FORMAT_XML && format != FORMAT_TEXT){

        if (format != FORMAT_XML && format != FORMAT_TEXT){
            if (netconf_operation_failed(cbret, "application", "Format not supported")< 0)
                goto done;
            goto ok;
        }