shairport-sync: fix init script

'name' may contains '%h' or '%v', printf will fail on that

Signed-off-by: Liangbin Lian <jjm2473@gmail.com>
(cherry picked from commit 97ec5d2a68)

sound/shairport-sync/files/shairport-sync.init

@@ -26,7 +26,7 @@ append_str() {
 
 	config_get val "$cfg" "$var"
 	if [ -n "$val" ] || [ -n "$def" ]; then
-		printf "\t%s = \"${val:-$def}\";\n" "$opt"
+		printf "\t%s = \"%s\";\n" "$opt" "${val:-$def}"
 	fi
 }