retrace: Explicitly add opsys release; improve error handling

- Explicitly register supported CentOS and Fedora releases using
  `faf releaseadd`.
- Ignore "errors" of the "already defined" kind.

roles/abrt/faf-post/tasks/main.yml

@@ -1,4 +1,6 @@
 ---
+- import_tasks: opsys_and_releases.yml
+
 - import_tasks: repositories.yml
 
 - name: Ensure directory for FAF database backups exists

roles/abrt/faf-post/tasks/opsys_and_releases.yml

@@ -0,0 +1,19 @@
+---
+- name: Add CentOS opsys releases
+  loop: "{{ rs_internal_centos_vers }}"
+  shell: >
+    faf releaseadd -o centos --opsys-release {{ item }} -s ACTIVE
+  become: yes
+  become_user: faf
+  register: result
+  failed_when: result.rc != 0 and 'already defined' not in result.stderr
+
+- name: Add Fedora opsys releases
+  loop: "{{ rs_internal_fedora_vers }}"
+  shell: >
+    faf releaseadd -o fedora --opsys-release {{ item }} -s ACTIVE
+  become: yes
+  become_user: faf
+  register: result
+  failed_when: result.rc != 0 and 'already defined' not in result.stderr
+...

roles/abrt/faf-post/tasks/repositories.yml

@@ -5,7 +5,8 @@
     faf repoadd --nogpgcheck "{{ item.name }}" dnf "{{ item.url | join('" "') }}"
   become: yes
   become_user: faf
-  ignore_errors: yes
+  register: result
+  failed_when: result.rc != 0 and 'already defined' not in result.stderr
   tags: add_repo
 
 - name: Assign repositories to Fedora releases