title: SonarQube Scanner fails in a Jenkins pipeline due to command not found
body: <p>I'd like to run SonarQube Scanner from a Jenkins pipeline and I followed the documentation.</p>
  
  <p>Regarding the error, it seems that the scanner is present but some commands are not found. My jenkins instance runs in a docker.</p>
  
  <p>Jenkins version : 2.46.1</p>
  
  <p>SonarQube Scanner : 2.6.1</p>
  
  <pre><code>+ /var/lib/jenkins/tools/hudson.plugins.sonar.SonarRunnerInstallation/SonarQube_Scanner/bin/sonar-scanner
  /var/lib/jenkins/tools/hudson.plugins.sonar.SonarRunnerInstallation/SonarQube_Scanner/bin/sonar-scanner: line 56: which: command not found
  /var/lib/jenkins/tools/hudson.plugins.sonar.SonarRunnerInstallation/SonarQube_Scanner/bin/sonar-scanner: line 66: exec: : not found
  </code></pre>