launch output is wrong in several ways

[Peter Matulis]

The output provided by the microstack.launch command is wrong on a few counts.

Sample output here:

http://paste.ubuntu.com/p/rCjxdBkv5C/

1. Line 5 contains a wayward backtick
2. Line 5 should explicitly give the username ('cirros' for CirrOS image and 'ubuntu' for Ubuntu image)
3. Line 5 hardcodes the default SSH key. It should show the one that was actually used.

[Pen Gale (pengale)]

Yep. All that needs fixing! Points #2 and #3 are a little fiddly, but would make an excellent task for anybody wanting to get their feet wet contributing!

[Pen Gale (pengale)]

Merge proposal here: https://review.opendev.org/#/c/696764/

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/696764
Committed: https://git.openstack.org/cgit/x/microstack/commit/?id=d169bef11932d77f519abf2744e7a2914b5cb088
Submitter: Zuul
Branch: master

commit d169bef11932d77f519abf2744e7a2914b5cb088
Author: Pete Vander Giessen <email address hidden>
Date: Fri Nov 29 22:23:43 2019 +0000

    Fixed launch output.

    Fixed backticks so that they actually wrap the whole command.

    Added code to gamely make a guess about the username of the launched
    instance and the location of the ssh key. Falls back on placeholders
    if it can't.

    Closes-bug 1850586

    Change-Id: I980ee8617dfc4bf7c60846052d66ff18cf8aa8e9