Remove rally_requires_pip_packages

Given that the openstack_hosts role installs pip and virtualenv,
we do not need this extra task/var.

Change-Id: Id3c2329f0f0b86d88fcd748c7e4504400c942ef2

defaults/main.yml

@@ -52,10 +52,6 @@ rally_galera_database: rally
 rally_galera_user: rally
 rally_database_connection_string: mysql+pymysql://{{ rally_galera_user }}:{{ rally_galera_password }}@{{ rally_galera_address }}/{{ rally_galera_database }}?charset=utf8
 
-# Packages that must be installed before anything else
-rally_requires_pip_packages:
-  - virtualenv
-
 # These pins are sourced from the rally git repository's
 # upper-constraints file. These should be updated whenever
 # the rally pin is updated. The package pins here are only

tasks/rally_install.yml

@@ -33,19 +33,6 @@
       {% endfor %}
   when: rally_developer_mode | bool
 
-- name: Install requires pip packages
-  pip:
-    name: "{{ rally_requires_pip_packages }}"
-    state: "{{ rally_pip_package_state }}"
-    extra_args: >-
-      {{ rally_developer_mode | ternary(pip_install_developer_constraints | default('--constraint /opt/developer-pip-constraints.txt'), '') }}
-      {{ (pip_install_upper_constraints is defined) | ternary('--constraint ' + pip_install_upper_constraints | default(''),'') }}
-      {{ pip_install_options | default('') }}
-  register: install_packages
-  until: install_packages is success
-  retries: 5
-  delay: 2
-
 - name: Retrieve checksum for venv download
   uri:
     url: "{{ rally_venv_download_url | replace('tgz', 'checksum') }}"