Cron output mail lost with update to RELENG_7

[Kevin Oberman]

I have discovered a problem with the mail sent by cron jobs (I refer
only to logs, not invocations of mail from scripts.) They never are
delivered.
Mar  5 10:32:30 noc5 postfix/sendmail[1175]: fatal: root(0): No recipient addresses found in message header
Mar  5 10:32:30 noc5 postfix/sendmail[1175]: fatal: root(0): No recipient addresses found in message header
Mar  5 10:37:00 noc5 postfix/sendmail[1268]: fatal: root(0): No recipient addresses found in message header
Mar  5 10:37:00 noc5 postfix/sendmail[1268]: fatal: root(0): No recipient addresses found in message header

This showed up when I upgraded the system to RELENG_7 yesterday. My
previous install was RELENG_7 of May 2, 2009 and it delivered the logs
without any problems. No other changes were made. postfix was 2.6.5.

I have this same issue on all 8.0 systems I have, but I was blaming a
fault in postfix config. Now I realize that this is not the problem.

I really don't know quite where to look for this. Any clues would be
appreciated. 
-- 
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman at es.net			Phone: +1 510 486-8634
Key fingerprint:059B 2DDF 031C 9BA3 14A4  EADA 927D EBB3 987B 3751