This reverts commit 226094fbc483128c8888f4171c353aed738b8346.
A deprecation is a warning to something that use of a feature is
being discouraged. By definition it is not an error condition to
continue to use a deprecated feature.
A VIR_ERR_DEPRECATED constant thus makes no conceptual sense. For
features which are entirely absent we already document that the
VIR_ERR_NO_SUPPORT code will be used. There is no need to distinguish
between a feature which never existed and a feature which previously
existed and was since removed.
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>