Merge remote-tracking branch 'remotes/stsquad/tags/pull-travis-speedup-130318-1'...

Merge remote-tracking branch 'remotes/stsquad/tags/pull-travis-speedup-130318-1' into staging

Some updates to reduce timeouts in Travis

# gpg: Signature made Tue 13 Mar 2018 16:44:46 GMT
# gpg:                using RSA key FBD0DB095A9E2A44
# gpg: Good signature from "Alex Bennée (Master Work Key) <alex.bennee@linaro.org>"
# Primary key fingerprint: 6685 AE99 E751 67BC AFC8  DF35 FBD0 DB09 5A9E 2A44

* remotes/stsquad/tags/pull-travis-speedup-130318-1:
  .travis.yml: add --disable-user with the rest of the disables
  .travis.yml: split default config into system and user
  .travis.yml: drop setting default log output

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>