Update playbook improvements.

- Run on the different hosts in parallel, not waiting for other hosts to
finish.
- Handle an error when reboot_needed is not defined if a reboot is not
needed.
- Fix a typo.

update.yaml

 ---
-- name: Group hosts by package manager
+- name: Update hosts
+  strategy: host_pinned
   hosts:
     - all:!localhost
-  tasks:
-    - name: Group hosts by package manager
-      group_by:
-        key: pkg_mgr_{{ ansible_pkg_mgr }}
-      changed_when: false
   tags:
-        - always
-
-- name: Update Debian hosts
-  hosts:
-    - pkg_mgr_apt
+    - update
   tasks:
+    - name: Update Debian-based hosts
+      when: ansible_pkg_mgr == 'apt'
+      tags:
+        - debian
+      block:
         - name: Update packages
           apt:
             autoclean: true
@@ -60,36 +57,36 @@
               {{ apt_upgrade is changed or
               fwupdmgr is changed or
               flatpak_update is changed }}
-  tags:
-    - debian
-    - update
 
     - name: Update OpenWRT hosts
-  hosts:
-    - pkg_mgr_opkg
-  tasks:
+      when: ansible_pkg_mgr == 'opkg'
+      tags:
+        - openwrt
+      block:
         - name: Update package list
           command: opkg update
           changed_when: false
 
         - name: Update packages
-      # We run through sort so that we don't run 2 instances fo opkg at once.
-      shell: |-
-        opkg list-upgradable | awk '{print $1}' | sort | xargs -rn1 opkg upgrade
+          # We run through sort so that we don't run 2 instances of opkg at
+          # once.
+          shell: >-
+            opkg list-upgradable |
+            awk '{print $1}' |
+            sort |
+            xargs -rn1 opkg upgrade
           register: opkg_upgrade
           changed_when: opkg_upgrade.stdout_lines|length > 0
 
         - name: Set reboot needed fact
           set_fact:
             reboot_needed: "{{ opkg_upgrade is changed }}"
-  tags:
-    - openwrt
-    - update
 
-- name: Update OpenBSD hosts
-  hosts:
-    - pkg_mgr_openbsd_pkg
-  tasks:
+    - name: Update OpenWRT hosts
+      when: ansible_pkg_mgr == 'openbsd_pkg'
+      tags:
+        - openbsd
+      block:
         - name: Apply system patches
           command: syspatch
           register: syspatch
@@ -112,16 +109,13 @@
               {{ syspatch is changed or
               pkg_upgrade is changed or
               fw_update is changed }}
-  tags:
-    - openbsd
-    - update
 
 - name: Reboot NS1
   hosts:
     - ns1
   tasks:
     - name: Reboot
-      when: reboot_needed
+      when: reboot_needed|default(false)
       reboot:
   tags:
     - reboot
@@ -131,7 +125,7 @@
     - ea6350
   tasks:
     - name: Reboot
-      when: reboot_needed
+      when: reboot_needed|default(false)
       command: reboot
 
     - name: Wait to re-establish the connection
@@ -147,7 +141,7 @@
       wait_for_connection:
 
     - name: Reboot
-      when: reboot_needed
+      when: reboot_needed|default(false)
       reboot:
   tags:
     - reboot