title: GIT: merge two branches into a new one without dependencies in Gerrit
body: <p>I have two branches in my local repo: <strong>branch_1</strong> and <strong>branch_2</strong>, each is based on the same commit <strong>A</strong> and contains several commits (heads are <strong>A1</strong> and <strong>A2</strong> correspondingly). </p>
  
  <p>I pushed both of <strong>A1</strong> and <strong>A2</strong> to Gerrit <strong>master</strong> branch and have two separate reviews.
  Then, I abandoned them.</p>
  
  <p>Now I need to create a new local branch <strong>branch_3</strong> based on <strong>A</strong> and containing changes from both <strong>A1</strong> and <strong>A2</strong> into <strong>A3</strong>. I did:</p>
  
  <p><code>git checkout -b branch_3 origin/master</code></p>
  
  <p><code>git merge branch_1 branch_2</code></p>
  
  <p>I have got a commit <strong>A3</strong> that I need and pushed it to Gerrit.
  A third review was created, but it depended on two previous abandoned commits, therefore I cannot submit it.</p>
  
  <p>Is there any way to merge two branches into one commit <strong>A3</strong> so that it depends on only <strong>A</strong> but not <strong>A1</strong> and <strong>A2</strong>?</p>