Less postgis voodoo on travis

.travis.yml

@@ -23,14 +23,13 @@ addons:
   postgresql: "9.1"
 
 before_install:
+  - export DEBIAN_FRONTEND=noninteractive
   - sudo add-apt-repository ppa:ubuntugis/ppa -y
   - sudo add-apt-repository ppa:ubuntugis/ubuntugis-unstable -y # For postgresql-9.1-postgis-2.1
   - sudo add-apt-repository ppa:smspillaz/cmake-3.0.2 -y
   - sudo add-apt-repository ppa:kedazo/doxygen-updates-precise -y # For doxygen 1.8.8
-  - sudo rm -f /etc/apt/sources.list.d/pgdg-source.list # postgis from pgdg requires different gdal package than the grass package
   - sudo apt-get update -qq
-  - sudo apt-get remove postgresql-9.1-postgis-2.1 # Remove postgis from pgdg, will install postgis from ubuntugis-unstable instead
-  - sudo apt-get install --no-install-recommends
+  - sudo apt-get install --force-yes --no-install-recommends --no-install-suggests
                          bison cmake cmake-data doxygen flex git graphviz
                          grass-dev libexpat1-dev libfcgi-dev libgdal1-dev
                          libgeos-dev libgsl0-dev libpq-dev libproj-dev
@@ -41,7 +40,8 @@ before_install:
                          python python-dev python-qt4 python-qt4-dev
                          python-sip python-sip-dev spawn-fcgi txt2tags
                          xauth xfonts-100dpi xfonts-75dpi xfonts-base
-                         xfonts-scalable xvfb postgresql-9.1-postgis-2.1
+                         xfonts-scalable xvfb
+                         postgresql-9.1-postgis-2.1/precise # postgis one from ubuntugis-unstable, not pgdg
   - cmake --version
   - clang --version