some improvements to 'create stack user' path

* Increase the timeout from 3 to 10, so user has a bigger chance
  to kill the script if being run interactively before a 'stack'
  user is created.
* explicitly ask 'getent' for the stack user rather than getting
  all users and grepping (which would match an "openstack" user,
  or a user named "bob.stack")
* use $PWD rather than `pwd`
* create file in sudoers.d rather than modifying /etc/sudoers.
1 file changed