Fix missing permissions on Swift rebalance playbook

The playbook is executed as user heat-admin on the nodes, and some tasks
need to read and/or write to directories that are owned by the
containers (ie with a numeric id on the host itself).

Closes-Bug: 1759311
Change-Id: Ia766bc44a647fec15ff662f1ef9ffb67860b155b
(cherry picked from commit b78aeab4fd)

playbooks/swift_ring_rebalance.yaml

@@ -53,10 +53,12 @@
             src: /tmp/swift-rings.tar.gz
             dest: /{{ base_directory }}
             remote_src: yes
+            become: true
 
     - name: Get recon data
       command: cat /var/cache/swift/object.recon
       register: recon
+      become: true
 
     - name: Check if it is safe to continue rebalancing
       set_fact:
@@ -116,3 +118,4 @@
             src: /tmp/swift-rings.tar.gz
             dest: /{{ base_directory }}
             remote_src: yes
+            become: true