Use slurp to collect the swift ssh keys

Extracting the ssh public key using cat and storing the result in a
fact has resulted in periodic failures in the collection of the key,
and thereafter the failure to appropriately place that key into the
authorised_keys file.

This patch changes the collection method to use the Ansible slurp
module which has been found to be more reliable.

Closes-Bug: #1506291
Change-Id: I3ba5cdc944f38c67762860dc0d06bd5c35eeb269

playbooks/roles/os_swift_sync/tasks/swift_key_distribute.yml

@@ -16,7 +16,7 @@
 - name: Create authorized keys file from host vars
   authorized_key:
     user: "{{ swift_system_user_name }}"
-    key: "{{ hostvars[item]['swift_pubkey'] }}"
+    key: "{{ hostvars[item]['swift_pubkey'] | b64decode }}"
   with_items: groups['swift_all'] + groups['swift_remote_all']
   tags:
     - swift-key

playbooks/roles/os_swift_sync/tasks/swift_key_populate.yml

@@ -14,8 +14,8 @@
 # limitations under the License.
 
 - name: Get public key contents and store as var
-  command: |
-    cat {{ swift_system_home_folder }}/.ssh/id_rsa.pub
+  slurp:
+    src: "{{ swift_system_home_folder }}/.ssh/id_rsa.pub"
   register: swift_pub
   changed_when: false
   tags:
@@ -24,7 +24,7 @@
 
 - name: Register a fact for the swift pub key
   set_fact:
-     swift_pubkey: "{{ swift_pub.stdout }}"
+     swift_pubkey: "{{ swift_pub.content }}"
   tags:
     - swift-key
     - swift-key-create