Use attribute from rabbitmq node to get rabbitmq IP address

The rabbitmq cookbook saves the IP address used by rabbitmq to listen,
so no need to do some fancy thing to get it.
Use helper from database cookbook to get database IP address

This way we're ready for when HA will be used for database.
Merge pull request #99 from vuntz/db-ha

Get ready for HA in database and rabbitmq
Update passwords migration script to remove node attributes

On update, we want to use the db password (and metering secret) from the
proposal / role, and not the ones that might have been generated on the node
(through the cookbook). As the passwords are a "normal" attribute on the node,
but a "default" attribute on the role, the old ones from the node is used.
Which means we really need to remove them to get the new ones used.

To minimize config changes, we actually import the passwords from one
node (which should be good enough in most cases as we allow only one
ceilometer proposal, so only one node should have the passwords).
Use new synchronization helpers to avoid races when deploying with HA

There are a number of possible races when deploying ceilometer for the
first time:

 - when creating of the database / database user
 - when registering the endpoint and creating users in keystone
 - running the db sync
Wait for mongodb on all nodes of the cluster, not just the founder
Merge pull request #101 from vuntz/drop-db-node

Update passwords migration script to remove node attributes
Merge pull request #102 from vuntz/sync-marks

Use new synchronization helpers to avoid races when deploying with HA
Configuration of active-pasive HA for ceilometer-agent-central:

Creating cluster resource configuration for pacemaker.

use LSB service until OCF agent is able to use LSB services internally

use PacemakerServiceObject's helper
Manage ceilometer-api services via pacemaker clone LWRP
Add synchronization marks around the creation of pacemaker resources
Added ceilometer pacemaker support for collector service and
group it with ceilometer api as server-group