abuild, abuild-keygen: drop echo -n as well

abuild-keygen.in

@@ -33,7 +33,7 @@ get_privkey_file() {
 	privkey="$ABUILD_USERDIR/$default_name.rsa"
 	[ -n "$non_interactive" ] && return 0
 	msg "Generating public/private rsa key pair for abuild"
-	echo -n "Enter file in which to save the key [$privkey]: "
+	printf '%s' "Enter file in which to save the key [$privkey]: "
 
 	read line
 	if [ -n "$line" ]; then