Be clear about python3: Remove its support

We have never really tested python3 at large scale, and more and
more bugs are filed in stable branches due to dual stack.

We should stick to python2 in the stable branches, which is
what was tested in our gates.

Change-Id: Id4d6dcb6892a7f3b67ee383a29fbbf2771452e9d

defaults/main.yml

@@ -22,9 +22,6 @@ almanach_service_names:
   - "almanach-api"
   - "almanach-collector"
 
-almanach_requires_apt_packages:
-  - python3-pip
-
 almanach_requires_pip_packages:
   - virtualenv
 

tasks/almanach_install.yml

@@ -13,20 +13,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-- name: Update APT index
-  apt: update_cache=yes
-  become: True
-
-- name: Install apt packages
-  apt:
-    name: "{{ almanach_requires_apt_packages | join(' ') }}"
-    state: present
-
 - name: Install pip packages
   pip:
     name: "{{ almanach_requires_pip_packages }}"
     state: present
-    executable: pip3
 
 - name: Install Almanach
-  pip: name=almanach version={{ almanach_version }} virtualenv={{ almanach_app_dir }} virtualenv_python=python3
+  pip:
+    name: almanach
+    version: "{{ almanach_version }}"
+    virtualenv: "{{ almanach_app_dir }}"
+    #virtualenv_python: "python2"