title: Gitlab multi pipeline override variable passed to new pipelines
body: <p>I am testing the new multi project functionality for Gitlab where I can trigger the next pipeline from my current pipeline:
  <a href="https://docs.gitlab.com/ee/ci/multi_project_pipelines.html" rel="nofollow noreferrer">https://docs.gitlab.com/ee/ci/multi_project_pipelines.html</a></p>
  <p>I only have one problem. I have two pipelines A and B. in both pipelines I define global variables in the yaml file.</p>
  <p>Pipeline A:</p>
  <pre><code>variables:
      Name: 'vw-$CI_PIPELINE_ID'
  stages:
      - hello
      - trigger
  hello:
      stage: hello
      script:
          - Write-Host &quot;Hello World&quot;
  trigger:
      stage: trigger
      trigger: 
          project: my/PipelineB
          branch: master
  </code></pre>
  <p>Pipeline B</p>
  <pre><code>variables:
      Name: 'vw-$CI_PIPELINE_ID'
  stages: 
      - triggered
  triggered:
      stage: triggered
      script: 
          - write-host $Env:Name
  </code></pre>
  <p>Expectation is that the variables would be overwritten in Pipeline B.</p>
  <p>Actual outcome is the variable has the same value as defined in Pipeline A</p>