Update PostgreSQL version in Travis since we want it to listen on port 5432.
How to test this PR
Travis should pass (or not if #1132 is not merged).
Travis should be successful in launching the backend tests (meaning preparing the environment should succeed for all tests).
Purpose
Fix Travis.
Context
n/a
Changes
Update PostgreSQL version in Travis since we want it to listen on port 5432.
How to test this PR
Travis should pass (or not if #1132 is not merged). Travis should be successful in launching the backend tests (meaning preparing the environment should succeed for all tests).