base-files: always generate default DUID

The previous logic was copied from 12_network-generate-ula, but fails to
account for upgrades where the "auto" value isn't set (it is set by
base-files/files/bin/config_generate). Fix this to always set the
default duid if it isn't set.

Also, rename the file to better reflect what it does.

Closes: #21029
Fixes: a660a076db5a ("base-files: generate a global DHCP DUID")
Link: https://github.com/openwrt/openwrt/pull/21118
Signed-off-by: David Härdeman <[email protected]>
Signed-off-by: Petr Štetiar <[email protected]> [fixes,closes tag]

package/base-files/files/etc/uci-defaults/14_network-generate-clientid → package/base-files/files/etc/uci-defaults/14_network-generate-duid

@@ -1,4 +1,4 @@
-[ "$(uci -q get network.globals.dhcp_default_duid)" != "auto" ] && exit 0
+[ "$(uci -q get network.globals.dhcp_default_duid || echo "auto")" != "auto" ] && exit 0
 
 uci -q batch <<-EOF >/dev/null
 	# DUID-UUID - RFC6355