clean up attributes for mq and database

There are currently a wide variety of naming schemas and places defining the current attributes for the mq and db services. The proposal is to unify them under a consistent pattern and only define them in the openstack-common cookbook. openstack-common is the logical location for them because openstack-ops-database and openstack-ops-messaging are considered "reference implementations" and other cookbooks depend on their attributes. Setting them centrally keeps them logically constrained.

The proposed consistent naming schema is to put the database attributes under

    node['openstack']['db']
    node['openstack']['db']['platform']
    node['openstack']['db']['service_type']
    node['openstack']['db']['bind_interface']

Anything specific to a database implementation would be nested under the particular service type. For example

    db_type = node['openstack']['db']['service_type']

    node['openstack']['db'][db_type]['cluster'] = false
    node['openstack']['db'][db_type]['host'] = '127.0.0.1'

    node['openstack']['db']['mysql']['port'] = '3306'
    node['openstack']['db']['mysql']['root_user_key'] = 'mysqlroot'

or similarly for messaging

    node['openstack']['mq']['qpid']['heartbeat'] = 60
    node['openstack']['mq']['qpid']['host'] = '127.0.0.1'
    node['openstack']['mq']['qpid']['password'] = ''
    node['openstack']['mq']['qpid']['port'] = '5672'

For OpenStack services that may need to have specific settings, the namespace is
    node['openstack']['db'][SERVICE]

    node['openstack']['db']['compute']['db_name'] = 'nova'
    node['openstack']['db']['compute'][db_type]['host'] = '127.0.0.1'
    node['openstack']['db']['compute'][db_type]['port'] = node['openstack']['db'][db_type]['port']

or similarly for messaging

    node['openstack']['mq']['compute']['qpid']['reconnect_interval_min'] = 0
    node['openstack']['mq']['compute']['qpid']['reconnect_limit'] = 0
    node['openstack']['mq']['compute']['qpid']['reconnect_timeout'] = 0

The proposed changes are:
1) All node[openstack][db] attributes will be defined in openstack-common/attributes/database.rb and removed from openstack-ops-database and other OpenStack cookbooks.
2) All node[openstack][mq] attributes will be defined in openstack-common/attributes/messaging.rb and removed from openstack-ops-messaging and other OpenStack cookbooks.
3) The attribute namespaces will be consolidated as described above.