socklog: disable shsgr test

Running the chkhsgr test on Hydra fails with
```
./chkshsgr || ( cat warn-shsgr; exit 1 )
Oops. Your getgroups() returned 0, and setgroups() failed; this means
that I can't reliably do my shsgr test. Please either ``make'' as root
or ``make'' while you're in one or more supplementary groups.
```

We just assume that our supported platforms have working
getgroups()/setgroups().