[Ubuntu] New PostGIS update

[Jerome Villeneuve Larouche]

Hello,

As I have been told by Even Rouault, the new PostGIS 2.0.3 update has 
some package changes which may cause some problems to create new PostGIS 
DB. The extensions scripts are now in a package called 
"postgresql-9.1-postgis-2.0-scripts".

Thanks to Even because I didn't think about it when pushing the package 
:S and sorry for any inconvenience.

Jérôme