cmd/docker: do not print error status on exec/run

[Benehiko]

- What I did
Do not print to std.Err when using docker exec.

• Replaces, closes Fix tainted stderr on docker exec #5852

- How I did it
Be explicit on printing the Cause/Status from StatusError instead of a fallback to a generic error message.

- How to verify it

- Human readable description for the release notes

Fix unintentionally printing exit status to stderr when `docker exec/run` returns a non-zero status

- A picture of a cute animal (not mandatory but encouraged)

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 20.00000% with 4 lines in your changes missing coverage. Please review.

Project coverage is 59.27%. Comparing base (eb48cad) to head (0cff340).
Report is 2 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5854      +/-   ##
==========================================
+ Coverage   58.89%   59.27%   +0.37%     
==========================================
  Files         350      353       +3     
  Lines       29682    29694      +12     
==========================================
+ Hits        17482    17601     +119     
+ Misses      11218    11113     -105     
+ Partials      982      980       -2     

[thaJeztah]

LGTM

@neersighted @vvoland @laurazard PTAL

[thaJeztah]

I guess if we want to be strict in our tests, we could consider checking for the error message to be empty (with a comment);

assert.Check(t, is.Equal(err.Error(), ""), "should not print our own error message, as the container's output is the error message")

Not urgent for how, but something we could consider

[thaJeztah]

Derp; meant checking the d.String() for what we expect it to output (for that we could add a echo "something failed" to the container's command.

(but again, probably fine to look at in a follow up)

[vvoland]

LGTM

[vvoland]

Note: This also fixes run so the title/changelog should be adjusted

[thaJeztah]

Heh; probably best to update the commit message, not just the PR title 😂 😇

[Benehiko]

Heh; probably best to update the commit message, not just the PR title 😂 😇

too many places to update 🙈
PR title, changelog, commit title

[thaJeztah]

LGTM

yeah, bit of a hassle always; sometimes help finding back changes in git history though!

[felixfontein]

Is it possible to get a 28.0.1 release soon with this fix included?