[dev] some updates for making Xenial default env

[redshiftzero]

Status

Ready for review

Description of Changes

Two more checkboxes in #4155, an easy merge

Testing

• Check I got all the application-level references to the make test* targets in the application level makefile
• Check I got all the 14.04 references in the Vagrantfile

Deployment

None, we're recommending Xenial in prod already

[emkll]

Running into some issues running make test locally, there appears to be a problem building the Docker image:

Processing triggers for dbus (1.10.6-1ubuntu3.3) ...
Errors were encountered while processing:
 libglib2.0-cil
 libglib2.0-cil-dev
 libgtk2.0-cil
 libgtk2.0-cil-dev
E: Sub-process /usr/bin/dpkg returned an error code (1)
The command '/bin/sh -c apt-get update &&     apt-get install -y devscripts                        python-pip libpython2.7-dev libssl-dev secure-delete                        gnupg2 ruby redis-server firefox git xvfb haveged curl                        gettext paxctl x11vnc enchant libffi-dev sqlite3 gettext sudo                        libgtk2.0' returned a non-zero code: 100
Makefile:21: recipe for target 'test' failed
make: *** [test] Error 1

Is anyone else seeing this?

[eloquence]

Can't reproduce locally with make test, output for me appears identical to the one in CircleCI (including the warning).

[kushaldas]

Approved. I guess we will update the docs in a separate PR.

docs/development/virtual_environments.rst is the file requires more work.

[heartsucker]

I blew away my docker cache and cannot reproduce this error. I'm going to merge, but if this persists, we should open a follow up.

[emkll]

Thanks @heartsucker . For those experiencing these issues, docker system prune -a does indeed resolve the issue for me.