Use 'command -v' to make shellcheck happy

gen-sshd-host-keys

@@ -47,7 +47,7 @@ create_key() {
 		printf "%s" "$msg"
 		ssh-keygen -q -f "$file" -N '' "$@"
 		echo
-		if which restorecon >/dev/null 2>&1; then
+		if command -v restorecon >/dev/null 2>&1; then
 			restorecon "$file" "$file.pub"
 		fi
 		ssh-keygen -l -f "$file.pub"