title: Unable to retrieve git submodule in jenkins with git-client plugin
body: <p>I'm trying to have Jenkins retrieve the submodules of a repository, but I cannot get it to work. I've looked around on the internet for a solution, but most problems there center around authentication, which is not the issue in this case. From what I've been able to gather from the error message, the issue seems to be related to the way the git-client plugin handles reponses from the command-line tools.</p>
  
  <p>As we had Git for Windows version 2.6.0 installed and the Jenkins Git-client plugin 'officially' supports version 2.5.0, I also tried uninstalling version 2.6.0 and installed version 2.5.0, but that made no difference.</p>
  
  <p>Does anyone here have any experience with this problem or a possible solution?
  The error is:</p>
  
  <pre><code>FATAL: Command "c:\Program Files\Git\bin\git.exe submodule update" returned status code 1:
  stdout: 
  stderr: Cloning into 'mysubmodule'...
  error: cannot spawn echo : No such file or directory
  bash: /dev/tty: No such device or address
  error: failed to execute prompt script (exit code 1)
  fatal: could not read Username for 'http://somerepo': No error
  Clone of 'http://somerepo/scm/bf/mysubmodule.git' into submodule path 'mysubmodule' failed
  </code></pre>