Populate dns - Closes #409

Implement extract from LDAP to populate pdns.keystone_project. This is then used in the records_[foward|reverse] views to generate A and PTR records for VMs with associated floating IPs. 

* creates a new Python script: /usr/local/bin/populate_dns.py
* updates root's cron job to run this script every minute instead of the mysql function directly
* create a new table, keystone_project, in pdns to hold required data in lieu of keystone.project
* updates records_[forward|reverse] views to pull from pdns.keystone_project instead of keystone.project

This was necessitated by the conversion of keystone backing from mysql to ldap.