Revert "Fix "Usage" to work with debian system."

This reverts commit 66adcf12f9c87da1eeea87c53286b6c4528c015f.

Patch author writes:

  I agree with Nadav. My patch change the original meaning of document.  My way
  for debian results in start OSv without bridge network. So please drop this
  patch, Pekka.