[exim] pid log selector

Hi,

I use the Exim test suite to test configuration changes. It's worked
reasonably well until now, except for certain tests. For example, testing
callouts to domains with multiple MX records can fail. Also, cached lookups
yield different log entries when the cache expires.

There's a new source of variability introduced with Exim 4.67: the log
selector "pid". My view is that this should be disabled when running Exim
in the test harness.

Of course, the workaround is to remove it from the configuration and put it
back before deployment. That's not ideal, though, since the idea is to NOT
change the configuration after testing.

Hmm, perhaps I just don't need the pid logged...

--
Ian Eiloart
IT Services, University of Sussex
x3148