Add 'debian' user in bootstrapServer()
Add 'debian' user in bootstrapServer()

The method attempt to login as 'root' then iterate a few well known
usernames.  Debian recommands using 'debian'.

Change-Id: If3f0f0137850e60780515c69329465837c4c91d8

seandst/nodepool,Tesora/tesora-nodepool,Tesora/tesora-nodepool,citrix-openstack/nodepool,citrix-openstack/nodepool,seandst/nodepool