tvheadend: skip the DVB permission fix without adapters

start_service() runs chgrp and chmod on /dev/dvb/*. Without a DVB
adapter the pattern does not match, so every start, including the one
during a package upgrade, prints

    chgrp: /dev/dvb/*: No such file or directory
    chmod: /dev/dvb/*: No such file or directory

Only touch the entries that exist. The fix itself is still needed for
adapters that were plugged in before the package was installed, as no
hotplug event sets their group then.

Signed-off-by: Josef Schlehofer <pepe.schlehofer@gmail.com>

multimedia/tvheadend/files/tvheadend.init

@@ -81,10 +81,13 @@ load_uci_config() {
 
 start_service() {
 	ensure_config_exists
+	for dev in /dev/dvb/*; do
+		[ -e "$dev" ] || continue
+		chgrp -R $TVH_GROUP "$dev"
+		chmod -R g+rwX "$dev"
+	done
 	procd_open_instance
 	procd_set_param file /etc/config/tvheadend
-	chgrp -R $TVH_GROUP /dev/dvb/*
-	chmod -R g+rwX /dev/dvb/*
 	procd_set_param command "$PROG" -B -u $TVH_USER -g $TVH_GROUP
 	load_uci_config
 	procd_close_instance