Remove httplib2 install from tests

httplib2 is an old ansible requirement for the uri/url
module which is no longer necessary.

Change-Id: I5b53c7b0655e7cbb1ff34a21a53ed17c38a6d17f

tests/test-zaqar-functional.yml

@@ -17,13 +17,10 @@
   hosts: zaqar_all
   user: root
   gather_facts: false
+  vars_files:
+    - common/test-vars.yml
   tasks:
-    - name: Install testing pip packages
-      pip:
-        name: "httplib2"
     - name: Check the zaqar-api
       uri:
         url: "http://localhost:8888"
         status_code: 401
-  vars_files:
-    - common/test-vars.yml