Use the host python interpreter when delegating to localhost

In order to ensure that the localhost delegated task uses the host
python interpreter (to access host-installed libs like
python-selinux), the interpreter is set on the task.

see: https://review.openstack.org/#/c/474565/

Change-Id: I7b20dd195a6562981fc5c72cbf7d91f6b45f4fa2

tasks/ceph_auth_extra.yml

@@ -31,6 +31,8 @@
     - item.mon_host is defined
     - item.keyring_src is defined
     - item.client_name is defined
+  vars:
+    ansible_python_interpreter: "/usr/bin/python"
 
 - name: Secure extra keyring file permissions
   file:
@@ -41,6 +43,8 @@
   with_items: "{{ ceph_extra_confs }}"
   when:
     - item.keyring_src is defined
+  vars:
+    ansible_python_interpreter: "/usr/bin/python"
 
 - name: Remove temp extra keyring files
   file:

tasks/ceph_auth_extra_compute.yml

@@ -30,6 +30,8 @@
   when:
     - item.mon_host is defined
     - item.client_name is defined
+  vars:
+    ansible_python_interpreter: "/usr/bin/python"
 
 - name: Distribute extra key files
   copy:
@@ -165,5 +167,7 @@
     state: "absent"
   delegate_to: localhost
   with_items: "{{ ceph_extra_confs }}"
+  vars:
+    ansible_python_interpreter: "/usr/bin/python"
   tags:
     - always

tasks/ceph_config_extra.yml

@@ -22,6 +22,8 @@
   when:
     - item.mon_host is defined
     - item.src is defined
+  vars:
+    ansible_python_interpreter: "/usr/bin/python"
 
 - name: Create extra ceph.conf files
   copy: