Remove pip_install dependency

With addition of pip_install on every node, we don't
need to have pip_install as a meta dependency.

Depends-On: If3412bb888ebb854874bbc43eb76bfcb3e4a7868
Depends-On: I79ff70c438b44753be2a93f004ebbc46de0a963d
Change-Id: I5ce8640cfb86af34694a0b8e308a5aa95cea8eaa

doc/source/index.rst

@@ -14,8 +14,12 @@ Default variables
    :language: yaml
    :start-after: under the License.
 
-Required variables
-~~~~~~~~~~~~~~~~~~
+Dependencies
+~~~~~~~~~~~~
+
+This role needs pip >= 7.1 installed on the target host.
+
+To use this role, the following variables must be defined:
 
 * ``rally_galera_address``
 * ``rally_galera_password``

meta/main.yml

@@ -25,7 +25,6 @@ galaxy_info:
         - xenial
   galaxy_tags: []
 dependencies:
-  - pip_install
   - role: apt_package_pinning
     when:
       - ansible_pkg_mgr == 'apt'