It seems that the .travis.yml was generated by make_travis_yml_2.hs
(099b33feb1) prior to there even being
a test-suite defined (5dd5bc4100).
Because 'cabal new-test' fails if there are no test suites, the
generator omits this command. Therefore even though there is a test
suite now, it is not being run in CI.
Add the command that make_travis_yml_2.hs would have generated if
there had been a test suite.
The version of 'directory' that gets installed with the 7.10 PPA is
too old. Tweak the environment for the 7.10 job to skip this step
and fix the build.
