remove plpython and python code for now. also removed mistaken installation of postgres_fdw in tests

src/pg/test/expected/01_install_test.out

@@ -1,6 +1,4 @@
 -- Install dependencies
 CREATE EXTENSION postgis;
-CREATE EXTENSION postgres_fdw;
-CREATE EXTENSION plpythonu;
 -- Install the extension
 CREATE EXTENSION observatory VERSION 'dev';

src/pg/test/sql/01_install_test.sql

@@ -1,7 +1,5 @@
 -- Install dependencies
 CREATE EXTENSION postgis;
-CREATE EXTENSION postgres_fdw;
-CREATE EXTENSION plpythonu;
 
 -- Install the extension
 CREATE EXTENSION observatory VERSION 'dev';