Silence warning about pattern.

Ref: https://git.adelielinux.org/adelie/packages/-/issues/1046

--- openrc-0.24.1/init.d/hwclock.in.old	2017-03-14 19:58:26.000000000 -0500
+++ openrc-0.24.1/init.d/hwclock.in	2023-10-02 01:02:49.249806693 -0500
@@ -75,7 +75,7 @@
 {
 	if ! yesno $clock_adjfile; then
 		# Some implementations don't handle adjustments
-		if LC_ALL=C hwclock --help 2>&1 | grep -q "\-\-noadjfile"; then
+		if LC_ALL=C hwclock --help 2>&1 | grep -q "\--noadjfile"; then
 			echo --noadjfile
 		fi
 	fi