[ticket/11970] Add set -x to Travis setup scripts.

Output is hidden by Travis by default and this will allow easier debugging.

PHPBB3-11970
[ticket/11970] Make apt-get less quiet.

PHPBB3-11970
Merge remote-tracking branch 'github-bantu/ticket/11970' into develop-olympus

* github-bantu/ticket/11970:
  [ticket/11970] Make apt-get less quiet.
  [ticket/11970] Add set -x to Travis setup scripts.
Merge branch 'develop-olympus' into develop

* develop-olympus:
  [ticket/11970] Make apt-get less quiet.
  [ticket/11970] Add set -x to Travis setup scripts.
Merge remote-tracking branch 'upstream/develop' into ticket/11975