Comment 19 for bug 1668093

Testing and shell into SRU for Xenial (others have the same, so just one is ok)
Former Version:
$ autopkgtest --apt-upgrade --shell --no-built-binaries openssh_7.2p2-4ubuntu2.1.dsc -- lxd ubuntu-daily:xenial/amd64
New Version:
$ autopkgtest --apt-upgrade --shell --setup-commands="add-apt-repository ppa:ci-train-ppa-service/2585; apt update; apt -y dist-upgrade" --no-built-binaries openssh_7.2p2-4ubuntu2.2.dsc -- lxd ubuntu-daily:xenial/amd64

Rerun full regression check
 $

Isolated execution of the Regression Test with:
 $ cd ${AUTOPKGTEST_TMP}/tree/regress
 $ env TEST_SHELL="sh" $(pwd)/test-exec.sh $(pwd) $(pwd)/keygen-knownhosts.sh

There are actually two tests that report "find simple in hashed".
The second one is the one failing:

rm -f $OBJ/kh.expect
expect_key host-h host-h host-f
check_hashed_find host-h "find simple in hashed" $OBJ/kh.hosts

That creates an expected hosts file and compares vs the created one.
In the bad case the result has 3x the same line, expected is just one (the content is good, just x3).

Expected is "constructed" by the script and always the same.
The input here is kh.hosts which shall be filtered for host-h.
The "special" thing on host-h is that it has multiple entries host-f, host-g, host-h

good case:
cat kh.hosts
# host-f
|1|qOQ8g9WMxPbnPpDWt+uKrbIDg+I=|CRVR2cmi1FQ2yOQOJI92OsewK0Y= ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIHu6oWC3VvOmfMSUXHCnCalWeV+BwsdbFohYI4pbt/bk host-f
|1|iR+WMF7scwVxrq6gMEvU7FDT3rw=|nKJaAF8aL7QBcrdhr5ktbvNpphc= ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIHu6oWC3VvOmfMSUXHCnCalWeV+BwsdbFohYI4pbt/bk host-f
|1|I7Fz/FqixsITHRgQMQ1qh3Z0MOs=|35k5Pgsdi26LnX8qEa/x5AA1Ra0= ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIHu6oWC3VvOmfMSUXHCnCalWeV+BwsdbFohYI4pbt/bk host-f
$ ssh-keygen -f kh.hosts -H -F host-h
|1|I7Fz/FqixsITHRgQMQ1qh3Z0MOs=|35k5Pgsdi26LnX8qEa/x5AA1Ra0= ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIHu6oWC3VvOmfMSUXHCnCalWeV+BwsdbFohYI4pbt/bk host-f

bad case:
cat kh.hosts
# host-f
host-f,host-g,host-h ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIJUaapZHmhvIshkUwydfXMBUucV8bDnJQzRr5w3KLvhC host-f
ssh-keygen -f kh.hosts -H -F host-h
|1|2F+CF0DKXdtLe0Hnb/4/uk82u7g=|oY3P3goocNH/nGO8I+851qQUBMQ= ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIJUaapZHmhvIshkUwydfXMBUucV8bDnJQzRr5w3KLvhC host-f
|1|ggIXIbTzzzTUU1boKmqEyIkzZEo=|7RZjQXl9O0GdwqwKJI7IVqnZq58= ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIJUaapZHmhvIshkUwydfXMBUucV8bDnJQzRr5w3KLvhC host-f
|1|mzIFYbXFU5rWYEAQVK1u+T4OaAM=|kXqon1yIIgUGSPQ5iJx4Qy97rHM= ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIJUaapZHmhvIshkUwydfXMBUucV8bDnJQzRr5w3KLvhC host-f

So in the old case it was already hashed when it got here in the test (that might be the failure actually).
Now since it is not hashed (yet) when it gets here the code generates 3x (one for each hostname) hashed entries.

Both agree on "kh.hosts.orig" content other than the actual generated pubs.

Next step: need to debug if the error is either:
1. that kh.hosts is different when it gets to the test
or
2. the handling by ssh-keygen on it then.