Merge pull request #66 from vuntz/helper-before-ha

Add a helper to get the listen address of the database
Create postgresql password in barclamp, not in cookbook

This way, it can be shared among multiple nodes.
Remove setting api_bind_host attribute in barclamp

This is unused.
Do not change db_maker user at every chef run

We were not using the right password to test if we could connect!
Initial support for HA by assuming shared storage

We do not handle in any way the shared storage here; it could be
something to look at.
Add ability to use shared storage