lxd-installer wait message confuses version checkers

[Simon Déziel]

The fact that lxd-installer echoes "Installing LXD snap, please be patient." to stdout while it `snap install lxd` behind the scene can confuse version checkers like `snapcraft`:

$ lxc launch ubuntu-minimal-daily:24.10 o1
$ lxc exec o1 -- apt-get update -qq
$ lxc exec o1 -- apt-get install --no-install-recommends -y git
$ lxc exec o1 -- git clone https://github.com/canonical/lxd-pkg-snap.git

$ lxc exec o1 -- snap wait system seed
$ lxc exec o1 -- snap install --classic snapcraft

$ lxc exec o1 -- sh -c 'cd /root/lxd-pkg-snap && snapcraft'
craft-providers error: Failed to parse LXD version.
Version data returned: 'Installing'
Full execution log: '/root/.local/state/snapcraft/log/snapcraft-20240618-151045.662527.log'

In the above, we see that `snapcraft` tried to interpret the first word on stdout ("Installing") as the LXD version but that's failing for obvious reasons.

lxd-installer should not output anything to stdout as that should be left to the real `lxd` and `lxc` commands.

[Launchpad Janitor (janitor)]

This bug was fixed in the package lxd-installer - 7

---------------
lxd-installer (7) oracular; urgency=medium

  * scripts/lxc: output to stderr only (LP: #2069754)
    - d/tests/install-on-demand: check user notification on stderr
  * Makefile: make `lxd` a symlink to /usr/sbin/lxc
  * d/control: bump standards-version to 4.7.0 (no change required)

 -- Simon Deziel <email address hidden> Tue, 18 Jun 2024 11:17:33 -0400