can not parse rpcuser's value which auto-generate

```
ubuntu@10-23-122-100:~$ cat /home/ubuntu/.multivac/multivac.conf
rpcuser=nX5ys1fJhOSjfHgjiYjvSd72IhE=
rpcpass=pcaWjlkrMOZNmAT1IRxJpngUbvc=
ubuntu@10-23-122-100:~$ ./MultiVAC
Error parsing Config file: /home/ubuntu/.multivac/multivac.conf:1: unknown option: rpcuser
Use MultiVAC -h to show usage
```