gluon-mesh-vpn-wireguard: fix empty string key

Co-Authored-By: Matthias Schiffer <mschiffer@universe-factory.net>

package/gluon-core/luasrc/usr/bin/gluon-info

@@ -22,8 +22,8 @@ local values = {
 	{ 'Hostname', pretty_hostname.get(uci) },
 	{ 'MAC address', sysconfig.primary_mac },
 	{ 'Hardware model', platform.get_model() },
-	{ 'Gluon version' .. " / " .. 'Site version', util.trim(util.readfile('/lib/gluon/gluon-version'))
-		.. " / " .. util.trim(util.readfile('/lib/gluon/site-version')) },
+	{ 'Gluon version / Site version', util.trim(util.readfile('/lib/gluon/gluon-version'))
+		.. ' / ' .. util.trim(util.readfile('/lib/gluon/site-version')) },
 	{ 'Firmware release', util.trim(util.readfile('/lib/gluon/release')) },
 	{ 'Site', site.site_name() },
 	{ 'Public VPN key', pubkey or 'n/a' },

package/gluon-mesh-vpn-wireguard/luasrc/usr/lib/lua/gluon/mesh-vpn/provider/wireguard.lua

@@ -7,7 +7,13 @@ local vpn_core = require 'gluon.mesh-vpn'
 local M = {}
 
 function M.public_key()
-	return util.trim(util.exec("/lib/gluon/mesh-vpn/wireguard_pubkey.sh"))
+	local key = util.trim(util.exec("/lib/gluon/mesh-vpn/wireguard_pubkey.sh"))
+
+	if key == '' then
+		key = nil
+	end
+
+	return key
 end
 
 function M.enable(val)