Fix password set length check

bin/create_user.sh

@@ -88,7 +88,7 @@ if [ ! -d "${HOME_FOLDER}" ]; then
 	error=1;
 fi;
 # allow 10 to 39 length for password
-if ! [[ "${PASSWORD_LENGTH}" =~ ^[13][0-9]$ ]]; then
+if [ ! -z "${PASSWORD_LENGTH}" ] && ! [[ "${PASSWORD_LENGTH}" =~ ^[13][0-9]$ ]]; then
 	echo "Password length set error, can only be a value between 10 and 39";
 	error=1;
 elif [ -z ${PASSWORD_LENGTH} ]; then