Rename commit variable

Rename the variable so it's more clear it's for the retro website.

roles/archweb/defaults/main.yml

@@ -47,4 +47,4 @@ archweb_db_backup_sequence_objs: 'ALL_IN_SCHEMA'
 
 archweb_retro_repository: 'https://git.archlinux.org/archweb-retro.git'
 archweb_retro_dir: '/srv/http/archweb-retro'
-archweb_commit_hash: '7eee8e20d3970c7c21ecef7ae8c9032e4b4a6d79'
+archweb_retro_commit_hash: '7eee8e20d3970c7c21ecef7ae8c9032e4b4a6d79'

roles/archweb/tasks/main.yml

@@ -311,7 +311,7 @@
   git:
     repo: "{{ archweb_retro_repository }}"
     dest: "{{ archweb_retro_dir }}"
-    version: "{{ archweb_commit_hash }}"
+    version: "{{ archweb_retro_commit_hash }}"
   become: true
   become_user: archweb
   when: archweb_site|bool