title: duplicate UUIDs warning on pod install post_install step
body: <p>When running the following in my podfile</p>
  
  <pre><code>post_install do |installer|
    installer.pods_project.targets.each do |target|
      if target.name == "React"
        target.remove_from_project
      end
    end
  end
  </code></pre>
  
  <p>I get these warnings:</p>
  
  <pre><code>[!] [Xcodeproj] Generated duplicate UUIDs:
  
  XCBuildConfiguration --
  XCBuildConfiguration --
  PBXBuildFile --
  PBXBuildFile --
  </code></pre>
  
  <p>What's causing this?  I noticed that I have some remnant tvOS targets in my schemes - is that a possible cause?</p>