specs: update spec_helper for Grand Renaming II™.

* specs/spec_helper.lua: Fix table_ext reference for name change
to straight table.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
travis: regenerate .travis.yml.

* .travis.yml: specl-8 is out, so don't try to work around it
any more!

Signed-off-by: Gary V. Vaughan <gary@gnu.org>