How to log the messages if a postscript fails during RPM installation ?

Issue

• The incorrect return code causes the post-install script to believe the package is install went well and there is no log about the failure.
• For example, if we update the packages using yum update, if any posttrans script fails, still yum.log will show the package as installed, however it will not work as expected.
• If we do not have console messages available, then we can not determine if any post script fails. Hence, yum should log the messages in the log file if any post script fails.