[QGIS-Developer] [PSA] Travis CI is up and running again

[Matthias Kuhn]

Hi,

Travis CI stopped working today and reported nothing but failures.

# The good news

It's up and running again.

# Affected pull requests

If you have a pull request which errored, either push a new commit to
your branch (if you have something that you wanted to push anyway) or
close and reopen the pull request.

# Cause

It was caused by the switch of the default distribution from precise to
trusty. (Read more about it here
https://blog.travis-ci.com/2017-07-11-trusty-as-default-linux-is-coming).
Right now it's quite easy to revert (once you know what's actually going
on).

# Perspective

Mid-term we will have to migrate to something newer though.
Travis also offers support for trusty but that's quite old as well. We
are currently looking into a couple of different approaches like
building our depencies for trusty and shipping them via a ppa or using a
docker container with the dependencies. The main requirement is that the
whole dependency build process is scripted and can be done
collaboratively (something the current osgeo4travis dependencies don't
fulfill which I'm eager to retire).

Cheers
Matthias