title: jenkins pipeline virtualenv plugin withPythonEnv
body: <p>On my custom jenkins pipeline, (pipeline virtualenv plugin installed before) I tried such code:</p>
  <pre><code>withPythonEnv('python3.5') {
       pysh 'pytest --cucumberjson=result.json testscript.py'
  }
  </code></pre>
  <p>But it still looks as targeting Python2.7 platform in console output of pipeline:</p>
  <blockquote>
  <p>pytest --cucumberjson=result.json testscript.py</p>
  <p>============== test session starts ================</p>
  <p>platform linux2 -- <strong>Python 2.7.13</strong>, pytest-3.6.3, py-1.5.4, pluggy-0.6.0</p>
  </blockquote>
  <p>On the other hand I run same py.test inside pycharm with venv of Python3.5 :</p>
  <blockquote>
  <p>platform linux -- <strong>Python 3.5.3</strong>, pytest-3.6.2, py-1.5.3, pluggy-0.6.0</p>
  </blockquote>
  <p>Any suggestions?</p>
  <p>Thanks in advance,
  Regards</p>