As of 436f10771 (make CommandStart return a StartMessage, 2019-06-06),
`find --json` no longer outputs json.

For example, with

[[!format sh """
cd $(mktemp -dt gx-find-json-XXXXXXX)
git init && git annex init
echo one >one && git annex add one && git commit -mone
git annex find --json -- one
"""]]

the last command outputs

```
one
```

rather than

```
{"bytesize":"4","mtime":"unknown","keyname":"2c8b08da5ce60398e1f19af0e5dccc744df274b826abe585eaba68c525434806","backend":"SHA256E","key":"SHA256E-s4--2c8b08da5ce60398e1f19af0e5dccc744df274b826abe585eaba68c525434806","humansize":"4 B","hashdirmixed":"0J/J1/","file":"one","hashdirlower":"171/8dc/"}
```

436f10771 appears to touch a lot of things, so perhaps other commands
show similar issues and `find` is just the first I noticed.

### On what operating system?

GNU/Linux, building git-annex with Guix

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

> [[fixed|done]] --[[Joey]]
