packaging: add Cosmic and Disco, remove Trusty and Artful
- Trusty was publicly supported until 2019-04-30
- Artful was publicly supported until 2018-07-19
- Cosmic was publicly supported until 2019-07-18
- Disco will be publicly supported until 2020-01
Cosmic is officially out-of-date, but since it still may be in use, and because
we didn't add it when it first came out, I think it would be nice to support it
until the next time somebody decides to update this list of Ubuntu releases.
Differential Revision: https://phab.mercurial-scm.org/D6761
$ hg init
$ touch unknown
$ touch a
$ hg add a
$ hg ci -m "1"
$ touch b
$ hg add b
$ hg ci -m "2"
Should show unknown
$ hg status
? unknown
$ hg revert -r 0 --all
removing b
Should show unknown and b removed
$ hg status
R b
? unknown
Should show a and unknown
$ ls
a
unknown