[Development] Needing another advise using git

[Daniel Savi]

Thank you all for the helpful comments on my previous message.

I think that I have now managed to amend my changes into one commit and 
may understand how to react on comments.

While amending my commits I must somehow have pushed another commit 
again that is not from me at all. It is this one: 
https://codereview.qt-project.org/#/c/207639/

I certainly did not intend to push this one. How should I proceed to 
delete this commit from my changes?