In main.cf:

smtp_header_checks = pcre:/etc/postfix/smtp_header_checks

In dynamicmaps.cf:

Use your real path to dict_pcre.so, below

pcre /usr/lib/postfix/dict_pcre.so dict_pcre_open

You should put this in your /etc/postfix/smtp_header_checks:

/^Received: .*/ IGNORE
/^X-Originating-IP:/ IGNORE

Then run

/etc/init.d/postfix reload