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: I5986a6588788b09501935fcd0fc18b96531bdca2
Closes-Bug: #1633438
Signed-off-by: Kevin Carter <kevin.carter@rackspace.com>

tasks/database-setup.yml

@@ -15,7 +15,7 @@
 
 - name: Check for db
   command: "{{ rally_bin }}/rally deployment list"
-  ignore_errors: true
+  failed_when: false
   register: rally_deployment_list_result
 
 - name: Create/upgrade Rally DB schema
@@ -25,7 +25,7 @@
 
 - name: Check for existing Rally deployment
   command: "{{ rally_bin }}/rally deployment list"
-  ignore_errors: true
+  failed_when: false
   register: rally_deployment_list_result
 
 - name: Setup the Rally deployment

tasks/install.yml

@@ -85,7 +85,7 @@
     url: "{{ rally_venv_download_url }}"
     dest: "/var/cache/{{ rally_venv_download_url | basename }}"
     force: yes
-  ignore_errors: true
+  failed_when: false
   register: get_venv
   when:
     - not rally_developer_mode | bool