Rename package lists (and related vars) appropriately

In order to make it easier to differentiate between the lists of
python packages, distribution packages, downloaded packages,
package pins and other similar variables the variable names are
being changed to ensure that they have a more explicit suffix
that defines the purpose and makes the naming more consistent.

This is to facilitate a lookup plugin which will be able to look
up all the package lists and present them as a consolidated piece
of data which may be used for artifact preparation.

Change-Id: Ibf9dda810f366b03c393ea6106c89e6ec49c5ee1

tasks/pre-install.yml

@@ -32,7 +32,7 @@
   until: install_deps | success
   retries: 5
   delay: 2
-  with_items: "{{ apt_packages }}"
+  with_items: "{{ monasca_distro_packages }}"
 
 - name: Add a kafka user with temp sudo permissions     # sudo removed in post-install.yml
   user:

tests/ansible-role-requirements.yml

@@ -30,4 +30,4 @@
 - name: rabbitmq_server
   src: https://git.openstack.org/openstack/openstack-ansible-rabbitmq_server
   scm: git
-  version: master
+  version: master

vars/ubuntu-14.04.yml

@@ -18,7 +18,7 @@
 #
 # Originally obtained from https://github.com/elastic/ansible-elasticsearch
 #
-apt_packages:
+monasca_distro_packages:
   - build-essential
   - chrony
   - git