Fix failure in distcheck and coverage tests

autotools/testrunner was missing in distcheck.  Now some changes from
70041061 have been reverted, and testrunner
is not built anymore.  coverage now uses fakeroot when needed.

Signed-off-by: Bernardo Dal Seno <bdalseno@google.com>
Reviewed-by: Michael Hanselmann <hansmi@google.com>