Fix storing of lan log segfault

[airween]

There is a bug report in e-mail (via mailing list), where the reporter explained the situation: if he uses Tlf on two nodes then when he enter a QSO the receiver node exists with SEGFAULT.

The problem is that the function parse_qso() is called two times, and it uses the char *buffer variable directly. When the function is called first time, the used strtok_r() chain "eats" the buffer, and at the second call it uses an empty buffer.

Here are the traces:

• 1st call
  • background_process.c:165
  • log_to_disk.c:121
  • log_utils.c:87
• 2nd call
  • log_to_disk.c:123
  • addcall.c:233
  • log_utils.c:87

Both calls are necessary for a complete log, so I think the best solution is to copy the original buffer and operate with that.