travis: install salt directly from PPA; bootstrap.saltstack.org is broken
travis: install salt directly from PPA; bootstrap.saltstack.org is
broken

The bootstrap-salt script sets up ppa:chris-lea/python-requests
python-requests won't install due to a broken dependency

The following packages have unmet dependencies:
 python-requests : Depends: python-urllib3 (>= 1.7.1) but it is not
installable
E: Unable to correct problems, you have held broken packages.
 * ERROR: Failed to run install_ubuntu_stable_deps()!!!

Signed-off-by: Gregory Meno <4c6f7d69a238d85f14b1affaec7960ea26aa1c6d@redhat.com>

r0h4n/ceph-integration