migration: fix missing assignment for has_x_checkpoint_delay

We forgot to assign true to params->has_x_checkpoint_delay parameter
in qmp_query_migrate_parameters.

Without this, qmp command 'query-migrate-parameters' doesn't show the
default value for x-checkpoint-delay option.

This also fixes the fact that HMP was relying on unspecified behavior by
reading x_checkpoint_delay without checking has_x_checkpoint_delay.
Signed-off-by: Nzhanghailiang <zhang.zhanghailiang@huawei.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

hmp.c

@@ -318,6 +318,7 @@ void hmp_info_migrate_parameters(Monitor *mon, const QDict *qdict)
         monitor_printf(mon, " %s: %" PRId64 " milliseconds",
             MigrationParameter_lookup[MIGRATION_PARAMETER_DOWNTIME_LIMIT],
             params->downtime_limit);
+        assert(params->has_x_checkpoint_delay);
         monitor_printf(mon, " %s: %" PRId64,
             MigrationParameter_lookup[MIGRATION_PARAMETER_X_CHECKPOINT_DELAY],
             params->x_checkpoint_delay);

migration/migration.c

@@ -593,6 +593,7 @@ MigrationParameters *qmp_query_migrate_parameters(Error **errp)
     params->max_bandwidth = s->parameters.max_bandwidth;
     params->has_downtime_limit = true;
     params->downtime_limit = s->parameters.downtime_limit;
+    params->has_x_checkpoint_delay = true;
     params->x_checkpoint_delay = s->parameters.x_checkpoint_delay;
 
     return params;