Convert runner2.archlinux.org to Arch

It was Debian previously.

host_vars/runner2.archlinux.org

+---
+hostname: "runner2.archlinux.org"
+
+ipv4_address: "147.75.80.217"
+ipv4_netmask: "/31"
+ipv6_address: "2604:1380:2001:4500::3"
+ipv6_netmask: "/127"
+ipv4_gateway: "147.75.80.216"
+ipv6_gateway: "2604:1380:2001:4500::2"
+filesystem: "btrfs"
+network_interface: "enp1s0f0np0"
+system_disks:
+  - /dev/sda
+configure_network: true

roles/gitlab-runner/tasks/main.yml

@@ -2,12 +2,6 @@
 
 - name: install dependencies
   pacman: name=docker,python-docker,python-gitlab,gitlab-runner state=latest update_cache=yes
-  when: ansible_facts['os_family'] == "Archlinux"
-  notify: restart gitlab-runner
-
-- name: install dependencies
-  apt: name=docker-ce,gitlab-runner state=latest update_cache=yes
-  when: ansible_facts['os_family'] == "Debian"
   notify: restart gitlab-runner
 
 - name: start docker