Fix python2 check

Print python_version to the console for debugging purposes
and fix the python2 check condition.

Change-Id: I31511d5ac848f4648b230221e1e11f711fb6b918

tasks/install-packages.yaml

@@ -44,13 +44,17 @@
       command: "python --version"
       register: python_version
 
-    - name: download get-pip.py
-      get_url: url=https://bootstrap.pypa.io/pip/2.7/get-pip.py dest=/tmp
-      when: '"2.7" in python_version.stdout'
+    - name: Print python version
+      debug:
+        var: python_version
 
-    - name: download get-pip.py
+    - name: download get-pip.py for python 2.7
+      get_url: url=https://bootstrap.pypa.io/pip/2.7/get-pip.py dest=/tmp
+      when: '"2.7" in python_version.stderr'
+
+    - name: download get-pip.py for ptython 2.6
       get_url: url=https://bootstrap.pypa.io/pip/2.6/get-pip.py dest=/tmp
-      when: '"2.6" in python_version.stdout'
+      when: '"2.6" in python_version.stderr'
 
     - name: install pip
       become: true