Run travis tests on postgresql 9.4

.travis.yml

@@ -6,9 +6,9 @@ otp_release:
   - 18.2
 before_script:
   - sudo apt-get update -qq
-  - sudo apt-get install postgresql-9.3-postgis-2.1 postgresql-contrib-9.3
+  - sudo apt-get install postgresql-9.4-postgis-2.1 postgresql-contrib-9.4
 addons:
-  postgresql: "9.3"
+  postgresql: "9.4"
 script:
   - sudo chmod 777 /var/run/postgresql/
   - ./setup_test_db.sh