When debugging some ssh-related datalad tests that hang with newer
git-annex versions, I noticed that there was a regression in the
treatment of annex-ssh-options in c8fec6ab0 (Fix a minor bug that
caused options provided with -c to be passed multiple times to git,
2020-03-16).

Here's a demo script.  Pointing `SSHURL` to any ssh-accessible annex
repo should do.  In the case below, the target is an annex repo with
one commit and no files in the working tree.

[[!format sh """
SSHURL="smaug:/home/kyle/scratch/repo"

cd "$(mktemp -d ${TMPDIR:-/tmp}/gx-ssh-opts-XXXXXXX)"
git clone "$SSHURL" ./ >/dev/null 2>&1
git annex init \
    -c annex.sshcaching=false \
    -c remote.origin.annex-ssh-options="-o ControlMaster=auto -S CACHE" \
    --debug 2>&1 | grep 'read: ssh'
"""]]

With the parent of the above commit checked out (b166223d4), the
script outputs

```
[2020-06-30 11:09:43.853918422] read: ssh ["smaug","-o","ControlMaster=auto","-S","CACHE","-n","-T","git-annex-shell 'configlist' '/home/kyle/scratch/repo' '--debug'"]
```

With c8fec6ab0 checked out, it outputs

```
[2020-06-30 11:11:03.833678263] read: ssh ["smaug","-S",".git/annex/ssh/smaug","-o","ControlMaster=auto","-o","ControlPersist=yes","-n","-T","git-annex-shell 'configlist' '/home/kyle/scratch/repo' '--debug'"]
[2020-06-30 11:11:04.448046366] read: ssh ["-O","stop","-S","smaug","-o","ControlMaster=auto","-o","ControlPersist=yes","localhost"]
```

It looks like the options specified via
`remote.origin.annex-ssh-options` are dropped, and git-annex switches
to using its built-in ssh caching.

A recent commit on master (95b8b4a5a) shows the same behavior.

I've tried to work through the config-related handling and understand
why the condition from c8fec6ab0 results in the ssh options being
dropped, but I haven't made any progress yet.

[[!meta author=kyle]]
[[!tag projects/datalad]]

> [[fixed|done]] (also re-fixed the original bug in a better way)
> --[[Joey]]