seedrng: use posix positional params to avoid space splitting

The value of ${seed_dir} may have spaces in it, making the current
argument string building method unsafe. Instead, use positional
parameters to pass these arguments safely.

init.d/seedrng.in

@@ -19,26 +19,26 @@ depend()
 	provide urandom
 }
 
-seedrng_options()
+seedrng_with_options()
 {
-	[ -n "${seed_dir}" ] &&
-		echo "--seed-dir \"${seed_dir}\""
-	yesno "${skip_credit}" &&
-		echo "--skip-credit"
+	set --
+	[ -n "${seed_dir}" ] && set -- "$@" --seed-dir "${seed_dir}"
+	yesno "${skip_credit}" && set -- "$@" --skip-credit
+	seedrng "$@"
 }
 
 start()
 {
 	ebegin "Seeding random number generator"
-	seedrng $(seedrng_options)
+	seedrng_with_options
 	eend $? "Error seeding random number generator"
 	return 0
 }
 
 stop()
 {
 	ebegin "Saving random number generator seed"
-	seedrng $(seedrng_options)
+	seedrng_with_options
 	eend $? "Error saving random number generator seed"
 	return 0
 }