t: Skip binaries-libc-link with old hardening-includes

As noted in [1], I suspect hardening-includes for being the culprit
for the weird "readelf: Error: 'EXEC': No such file" in Ubuntu
Precise.  For now, disable the test there (if only to stop travis from
spamming me with "it failed - yet again" mails).

[1] https://lists.debian.org/debian-lint-maint/2014/03/msg00177.html

Signed-off-by: Niels Thykier <niels@thykier.net>