Tools: Remove faulty exim configuration

The present exim configuration seems to contain a typo
("relay_domains" vs. "relay_to_domains") which fills
/var/log/exim4/paniclog with lines like:

| 2014-04-16 21:07:26 unknown named domain list "+relay_domains"
| 2014-04-16 21:07:38 unknown named domain list "+relay_domains"
| 2014-04-16 21:16:34 unknown named domain list "+relay_domains"

ad nauseam.  As the configuration doesn't allow for any relaying at
all, this change removes the dead code altogether.

The error has appeared more often only recently.  This suggests that
only recently something has started to try sending mails to a
non-local domain.

Change-Id: I20afa5fb2be7d8b9cf5c3bf4018377d0e847daef
Merge "Tools: Remove faulty exim configuration" into production