yum from cron setting http_proxy

[Neal D. Becker]

I set yum to run nightly, but there are problems.

1) I need http_proxy set.  I tried adding a script to /etc/profile.d, but
AFAICT, cron isn't executing it.  Any suggestions?  I don't want to modify
yum scripts, because I'm afraid my change will be lost - and this isn't
really yum specific.

2) There is no indication of any error in /var/log/cron
nor /var/log/yum.log.  I expect that running with the proxy, yum would time
out and die, but nothing is logged in either place.