delete "clean:test", because it replicate "clean:ct"
fix lintian error
add test.ct.coverspec config option

Summary: add test.ct.coverspec config option

Test Plan: on a project that has a cover spec run 'tetrapak test -o test.ct.coverspec <file>'

Reviewers: tbreddin, hsychla, kseidens, druss

Reviewed By: druss

Differential Revision: https://review.tpip.net/D103
Merge branch 'master' of git.tpip.net:tetrapak into travelping