Use monasca venv for influxdb setup

Instead of pip installing onto the host, we use the
influxdb in the monasca venv to do the influxdb database,
user, etc setup. This prevents interference between pip
installed packages and distribution packages, keeping the
line between host installed packages and venv installed
packages clean.

The venv is only deployed on the monasca_api servers, so
we change the group used for executing the tasks to the
right group for it to work.

Change-Id: I6e1f86a789f188dff611d522a3309a355f7cd8e8

tasks/monasca_db_setup.yml

@@ -12,7 +12,9 @@
 # limitations under the License.
 
 - include: monasca_influxdb_setup.yml
-  when: inventory_hostname in groups['monasca_influxdb']
+  when: inventory_hostname in groups['monasca_api']
+  vars:
+    ansible_python_interpreter: "{{ monasca_bin }}/python"
 
 - include: monasca_mysql_setup.yml
   when: inventory_hostname in groups['monasca_api']

tasks/monasca_influxdb_setup.yml

@@ -11,11 +11,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-- name: Install influxdb libs
-  pip:
-    name: influxdb
-    state: present
-
 - name: Create influxdb database
   influxdb_database:
     hostname: "{{ monasca_influxdb_host }}"