Make travis script simpler

.travis.yml

@@ -2,9 +2,8 @@
 # from Dolibarr GitHub repository.
 # For syntax, see https://docs.travis-ci.com/user/languages/php/
 
-# We use dist: xenial to have php 5.6+ available
+# We use dist: bionic = 18.04
 os: linux
-#dist: xenial
 dist: bionic
 
 language: php
@@ -38,8 +37,6 @@ addons:
   postgresql: '10'
   apt:
     sources:
-    # To use the last version of pgloader, we add repo of postgresql with a name available in http://apt.postgresql.org/pub/repos/apt/
-    - pgdg-xenial
     - sourceline: 'ppa:ondrej/php'
     packages:
     # We need a webserver to test the webservices