Workaround postgis package bugs in ubuntu repos (for travis)

.travis.yml

@@ -1,6 +1,10 @@
 before_install:
-  - sudo apt-add-repository --yes ppa:ubuntugis/ppa
+  #- sudo apt-add-repository --yes ppa:ubuntugis/ppa
   - sudo apt-get update -q
+  # Removal of postgresql-9.1-postgis-scripts is needed due to a
+  # bug in some upstream package.
+  # See http://trac.osgeo.org/ubuntugis/ticket/39
+  - sudo apt-get remove --purge -q postgresql-9.1-postgis-scripts 
   - sudo apt-get install -q postgresql-9.1-postgis gdal-bin
   - createdb template_postgis
   - psql -c "CREATE EXTENSION postgis" template_postgis