Use postgresql 9.5 for 3.8 and master branch #176.

.travis.yml

@@ -9,8 +9,7 @@ addons:
     packages:
     - openjdk-8-jre
 
-services:
-  - mysql
+dist: trusty
 
 cache:
   directories:
@@ -46,6 +45,11 @@ matrix:
       env: DB=mysqli MOODLE_BRANCH=MOODLE_33_STABLE
 
 before_install:
+  - export MOODLE_VERSION=$(echo "$MOODLE_BRANCH" | cut -d'_' -f 2)
+  - if [ ${TRAVIS_PHP_VERSION:0:3} == "7.2" ] && [ $DB == "pgsql" ] && [[ "$MOODLE_VERSION" -gt 38 || "$MOODLE_VERSION" == "master" ]] ; then
+      sudo /etc/init.d/postgresql stop;
+      sudo /etc/init.d/postgresql start 9.5;
+    fi
   - phpenv config-rm xdebug.ini
   - nvm install 8.9
   - nvm use 8.9