Do not report an error if the user already exists
Do not report an error if the user already exists

We would like to go to the next user if the user we are trying to create
return 409 that means a conflict has happened, so instead of add we need
to update, therefor we do not need to add an exception to the error
handler.

Signed-off-by: Salim Afiune <2b0aff3923bd0ab6bbf45ffb37e57dcea8e1b0b8@chef.io>

chef/knife-ec-backup,chef/knife-ec-backup