Remove 'ignore_errors: true' in favor of 'failed_when: false'

This change removes the use of 'ignore_errors: true' because it causes deployers
to see red output and a stacktrace, which traditionally means something is broken,
even when the failure is known to have a fall back option or be intentional. This
conversion will provide a generally cleaner interface.

It should be noted that the 'failed' filter will still function normally. Tasks
with the 'failed_when: false' option will still be marked as 'failed' in any
registered variable. This change simply makes the output look cleaner.

Change-Id: I358675701b72317db8522da7af68ed9ee56bcc54
Closes-Bug: #1633438
Signed-off-by: Kevin Carter <kevin.carter@rackspace.com>

scripts/upgrade-utilities/playbooks/deploy-config-changes.yml

@@ -27,7 +27,7 @@
 
       - name: Retrieve differences
         shell: rsync -avun "{{ repo_root_dir }}/playbooks/inventory/env.d/" "/etc/openstack_deploy/env.d/" | grep "yml$"
-        ignore_errors: yes
+        failed_when: false
         register: diff_result
 
       - name: Copy new env.d files into place

tests/roles/bootstrap-host/tasks/prepare_data_disk.yml

@@ -23,7 +23,7 @@
     parted --script -l -m | egrep -q ':ext4:openstack-data[12]:;$'
   register: data_disk_partitions
   changed_when: false
-  ignore_errors: yes
+  failed_when: false
   tags:
     - check-data-disk-partitions