Revert "travis-ci: use container based building"
Revert "travis-ci: use container based building"

This reverts commit 24c1c1780b44f973d1193d2adcb96af74cfa56f8.

Submitting a request for travis-ci team to whitelist libpam-dev
on the container building platform. Once approved, I will revert
this revert. https://github.com/travis-ci/travis-ci/issues/4421

rmbreak/pam_ldapdb