ETCD_UNSUPPORTED_ARCH not set in etcd 3.3 and 3.4

[George Kraft]

The ETCD_UNSUPPORTED_ARCH environment variable is not set in the etcd 3.3 and 3.4 snaps, which means that etcd will not run on unsupported architectures like arm64 and s390x.

ETCD_UNSUPPORTED_ARCH used to be set in the etcd 3.2 snap[1], but it looks like it was dropped from the 3.3 and 3.4 snaps[2][3] by mistake.

[1]: https://github.com/juju-solutions/etcd-snaps/blob/546baa1b2d666e172d83f58095333f993f9ab11a/bin/snap-wrap.sh#L38
[2]: https://github.com/juju-solutions/etcd-snaps/blob/v3.3/bin/snap-wrap.sh
[3]: https://github.com/juju-solutions/etcd-snaps/blob/v3.4/bin/snap-wrap.sh

[Tim Van Steenburgh (tvansteenburgh)]

PRs up for review:

https://github.com/juju-solutions/etcd-snaps/pull/22
https://github.com/juju-solutions/etcd-snaps/pull/23

[George Kraft (cynerva)]

This also fixes https://bugs.launchpad.net/etcd-snaps/+bug/1887539

[Tim Van Steenburgh (tvansteenburgh)]

Fix is in these snaps:

  3.4/stable: 3.4.5 2020-04-30 (230) 22MB -
  3.4/candidate: 3.4.5 2020-04-30 (230) 22MB -
  3.4/beta: 3.4.5 2020-04-30 (230) 22MB -
  3.4/edge: 3.4.5 2020-04-30 (230) 22MB -
  3.3/stable: 3.3.19 2020-07-21 (229) 21MB -
  3.3/candidate: 3.3.19 2020-07-21 (229) 21MB -
  3.3/beta: 3.3.19 2020-07-21 (229) 21MB -
  3.3/edge: 3.3.19 2020-04-07 (229) 21MB -