adelie-build-cd: Fix silly regex error

adelie-build-cd

@@ -188,7 +188,7 @@ make_structure() {
 	echo 'live::::::::' >> squashroot-$ARCH/etc/shadow
 	chown 1000:1000 squashroot-$ARCH/home/live
 
-	sed -i 's/pam_unix.so^/pam_unix.so nullok_secure/' squashroot-$ARCH/etc/pam.d/base-auth
+	sed -i 's/pam_unix.so$/pam_unix.so nullok_secure/' squashroot-$ARCH/etc/pam.d/base-auth
 
 	cat >squashroot-$ARCH/etc/shells <<- SHELLS
 		/bin/bash