Add DB2 support to ceilometer on redhat platform

Add a new attribute
default['openstack']['telemetry']['platform']['db2_python_packages']

Change-Id: I51c6974956ea5247f31f1d060cc8404610fab1d1
Implements: blueprint db2-support
Add recipes for alarm services

The telemetry cookbook currently lacks recipes for the alarm and the
agent notification services. This patch adds them as well as their
corresponding specs and documentation.

Implements blueprint alarm-sevices

Change-Id: I2896db6e95f52f4488ec8bb9bcb88c697cb712b6
Merge "Add DB2 support to ceilometer on redhat platform"
Use platform_family instead of platform

As agreed on the mailing list:
https://groups.google.com/forum/#!topic/opscode-chef-openstack/HEL3KqBQIUM

This will allow the ibm_powerkvm platform to be recognized.

Change-Id: Iebf2aad9f3b4649fb5c27d2fc93ee60c67e42737
Partially-Implements: blueprint add-ibm-powerkvm-enablement
Implements: blueprint platform-family
Fix service subscriptions and definitions, add package overrides

Some things were a little off wrt. the way we usually do stuff.  This
change fixes the following:

- package resources take the override settings from node attributes
- all services subscribe to their config file
- the service definitions include restart and status actions, and
  enable services

Change-Id: I3d4a2f9247dda34a35897fdfe08d9e8cf27556b8
Closes-Bug: #1303777
Merge "Fix service subscriptions and definitions, add package overrides"
Remove deprecated database_connection property

Instead use the new 'connection' property under the [database] group.

Change-Id: I4879803d38db954ef1d57777dd9be8545eb03769