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: Icd0afaaf8f0d9c5e06751f284f99985af6a924c6
Closes-Bug: #1633438
Signed-off-by: Kevin Carter <kevin.carter@rackspace.com>

tasks/openstack_kernel_modules.yml

@@ -42,7 +42,7 @@
   when:
     - openstack_host_specific_kernel_modules | length > 0
     - inventory_hostname in groups["{{ item.group }}"]
-  ignore_errors: yes
+  failed_when: false
 
 - name: fail if a specific kernel module is not set
   fail:

tasks/openstack_kernel_tuning.yml

@@ -21,4 +21,4 @@
     state: "{{ item.state|default('present') }}"
     reload: "{{ item.reload|default('yes') }}"
   with_items: "{{ openstack_kernel_options }}"
-  ignore_errors: true
+  failed_when: false