Remove the check latest packages version.

This validation can be removed. There is
a very similar playbook with the definition
of the package_list variable to check the version
of python-tripleoclient in the triple-validations
repository. This playbook is therefore not necessary.

Change-Id: I4b0a5916f93cf422def725fe2841c6867c7f1848

validations_common/playbooks/check-latest-packages-version.yaml

@@ -1,19 +0,0 @@
----
-- hosts: localhost
-  gather_facts: false
-  vars:
-    metadata:
-      name: Check if latest version of packages is installed
-      description: >
-        Makes sure a list of packages are at its latest version
-        before starting an upgrade.
-      groups:
-        - pre-upgrade
-      categories:
-        - packages
-        - rpm
-        - upgrade
-      products:
-        - common
-  roles:
-    - check_latest_packages_version