segfault in detail listener

[Alan DeKok]

Phil Mayers wrote:
> We're seeing very occasional segfaults in the detail listener. I've
> managed to catch one under gdb, and the backtrace shows it dying at
> detail.c:601:
> 
>  if (feof(data->fp)) goto cleanup;
> 
> ...because data->fp == NULL
> 
> I can't follow the control flow to see why this might happen, but I did
> gather a backtrace etc.

  <shrug>  The fix is easy.  Check if it's NULL.

  Pushed to git.

  Alan DeKok.