Display error message on BaseSection loop

[Crimsonum]

If the client's INI processor runs into a BaseSection loop*, the client will silently crash. No error message is displayed, and no crash log is generated. When such a crash occurs, the last line on the client log is <time_stamp> Initializing GameClass.. This makes it difficult for the modder to figure out why the client doesn't start.

*a case where BaseSection points to the parent section itself, i.e.

[FOO]
BaseSection=FOO