Fix the dependencies for ubuntugis-unstable

Fixes the Travis CI script. Dependency problems arose from packages renamed
on ubuntugis-unstable

On unstable, libgdal1 was renamed to libgdal1h. This is why the build stopped working even though the Travis-CI script hadn't changed. Other packages were renamed as well. Using postgresql-0.1-postgis-2.0 gets things working again. Alternatively, using the stable ppa would work.

See discussions:
http://lists.osgeo.org/pipermail/ubuntu/2013-July/000756.html