If message is not of type G_DBUS_MESSAGE_TYPE_ERROR does
nothing and returns FALSE.
Otherwise this method encodes the error in message as a GError
using g_dbus_error_set_dbus_error() using the information in the
G_DBUS_MESSAGE_HEADER_FIELD_ERROR_NAME header field of message as
well as the first string item in message's body.
Since 2.26
If message is not of type G_DBUS_MESSAGE_TYPE_ERROR does nothing and returns FALSE. Otherwise this method encodes the error in message as a GError using g_dbus_error_set_dbus_error() using the information in the G_DBUS_MESSAGE_HEADER_FIELD_ERROR_NAME header field of message as well as the first string item in message's body. Since 2.26