Fixed parsing process for AuthServer configurations

Currently `parse_auth_server` does not perform any blank-trimming to the property values of auth servers, for example, 
```
    Hostname 192.168.1.9        # your auth-serv hostname
```
would treat `"192.168.1.9        "` as the hostname, which would lead to a DNS failure in central server finding process. Same problem occurs when parsing path fragments configuration lines followed by trailing blanks/comments.

These commits trim the trailing blanks following the property value of AuthServer configuration lines, which could probably solve this problem.