title: git: remove files from an older commit
body: <p>I am working on a branch and I have made a couple of commits, in the first commit I had changed an interface to add a new method and then changed the implementation class as well.</p>
  
  <p>I have since found an existing method in the codebase that does pretty much what I want so I would like to check the files out in the first commit.</p>
  
  <p>I have only reset files in the previous commit before so I am not sure how to do this, in the past I had checked out the files I wanted to remove from an older commit but that created a new commit and also meant the file showed in crucible as part of the code review but without any changes to it.</p>
  
  <p>Could someone explain to me how to do this please?</p>