[JDBC] [pgjdbc/pgjdbc] e960f2: chore: install PostgreSQL 9.1 to Trustybuilds via...

  Branch: refs/heads/master
  Home:   https://github.com/pgjdbc/pgjdbc
  Commit: e960f2373a8de8b1b58fa199ee85a8b73ae684d2
      https://github.com/pgjdbc/pgjdbc/commit/e960f2373a8de8b1b58fa199ee85a8b73ae684d2
  Author: Vladimir Sitnikov <sitnikov.vladimir@gmail.com>
  Date:   2017-07-23 (Sun, 23 Jul 2017)

  Changed paths:
    M .travis.yml
    M .travis/travis_install_postgres.sh

  Log Message:
  -----------
  chore: install PostgreSQL 9.1 to Trusty builds via apt, and use Precise for Java 6

Travis deprecates Precise. See
https://blog.travis-ci.com/2017-07-11-trusty-as-default-linux-is-coming

sudo: required for dist: precise will still be supported for a while, however no updates to that image is planned

Java 6 is not included into Trusty image, and installers no longer work
(see http://www.webupd8.org/2017/06/why-oracle-java-7-and-6-installers-no.html) since
Oracle removed the installer files from public access.