title: buildroot - how to change kernel version string
body: <p>I work on SAM9G25 EK board with buildroot and Armstrong linux (Linux4sam).
  My script is creating linux version "2.6.39+" and this "+" is confusing (/lib/modules folder etc.). I want to remove it. I found only two files .uImage.cmd, and kernel.release that contains this string, but both are generated.</p>
  
  <p>Where is this string created ?</p>