travis: attempt to invoke Coverity scan after each build (fix coverity tar filename)

git-svn-id: https://svn.resiprocate.org/rep/resiprocate/main@10387 ddefafc4-47db-0310-ae44-fa13212b10f2
travis: attempt to invoke Coverity scan after each build (add support for arch detection)

git-svn-id: https://svn.resiprocate.org/rep/resiprocate/main@10388 ddefafc4-47db-0310-ae44-fa13212b10f2