Removed warning message from Ansible

Upgrade requires a string, not a boolean.

Issue-ID: CIMAN-33
Signed-off-by: Bengt Thuree <bthuree@linuxfoundation.org>
Change-Id: I0a03702e2cfb00b06e9a783fd5ce3b95dcee0e29
diff --git a/packer/provision/local-builder.yaml b/packer/provision/local-builder.yaml
index 162ac3f..3460981 100644
--- a/packer/provision/local-builder.yaml
+++ b/packer/provision/local-builder.yaml
@@ -14,7 +14,7 @@
 
     - name: Update and upgrade apt packages
       apt:
-        upgrade: yes
+        upgrade: 'yes'
         update_cache: yes
       become: true
       when: ansible_distribution == 'Ubuntu'
diff --git a/packer/provision/local-docker.yaml b/packer/provision/local-docker.yaml
index 5811270..0948cd0 100644
--- a/packer/provision/local-docker.yaml
+++ b/packer/provision/local-docker.yaml
@@ -79,7 +79,7 @@
 
     - name: Update and upgrade apt packages
       apt:
-        upgrade: yes
+        upgrade: 'yes'
         update_cache: yes
       become: true
       when: ansible_distribution == 'Ubuntu'