Use command module instead of shell as no shell functionality is required

Fixes this ansible-lint warning:

	[ANSIBLE0013] Use shell only when shell functionality is required
	/roles/fstrim/handlers/systemd-daemon-reload.yml:2
	Task/Handler: systemd-daemon-reload

handlers/systemd-daemon-reload.yml

@@ -1,3 +1,3 @@
 ---
 - name: systemd-daemon-reload
-  shell: systemctl daemon-reload
+  command: systemctl daemon-reload