Update release/dist script with preflight
Update release/dist script with preflight

Add a preflight check to ensure that AWS credentials is configured
before creating tag.

hashicorp/nomad,burdandrei/nomad,hashicorp/nomad,dvusboy/nomad,burdandrei/nomad,burdandrei/nomad,hashicorp/nomad,burdandrei/nomad,dvusboy/nomad,burdandrei/nomad,dvusboy/nomad,burdandrei/nomad,dvusboy/nomad,hashicorp/nomad,dvusboy/nomad,burdandrei/nomad,dvusboy/nomad,dvusboy/nomad,hashicorp/nomad,hashicorp/nomad