qdev: Use object_property_print() in info qtree

Otherwise, non-string properties without a legacy counterpart are missed.
Also fix error propagation in object_property_print() itself.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NAnthony Liguori <aliguori@us.ibm.com>
Signed-off-by: NAndreas Färber <afaerber@suse.de>

hw/qdev-monitor.c

@@ -493,7 +493,7 @@ static void qdev_print_props(Monitor *mon, DeviceState *dev, Property *props,
         if (object_property_get_type(OBJECT(dev), legacy_name, NULL)) {
             value = object_property_get_str(OBJECT(dev), legacy_name, &err);
         } else {
-            value = object_property_get_str(OBJECT(dev), props->name, &err);
+            value = object_property_print(OBJECT(dev), props->name, &err);
         }
         g_free(legacy_name);
 

qom/object.c

@@ -830,7 +830,7 @@ char *object_property_print(Object *obj, const char *name,
     char *string;
 
     mo = string_output_visitor_new();
-    object_property_get(obj, string_output_get_visitor(mo), name, NULL);
+    object_property_get(obj, string_output_get_visitor(mo), name, errp);
     string = string_output_get_string(mo);
     string_output_visitor_cleanup(mo);
     return string;