set passwords via attributes

previously we were relying on the get_password method in
openstack-identity to return its second argument, but now we can use
attributes to store passwords
call keystone_settings with @cookbook_name instead of :nova
enable mysql service, don't just start it
replace symbol indexing with single-quoted strings
set endpoint bind-host the same as the normal one

We don't support HA yet.
Merge pull request #4 from mapleoin/attrs

use more attributes for passwords