fix potential buffer overflow in test-server logging function

void logmsg(const char *msg, ...)

{

  va_list ap;

  char buffer[512]; /* possible overflow if you pass in a huge string */

  char buffer[2048 + 1];

  FILE *logfp;

  int error;

  struct timeval tv;

  now = localtime(&sec); /* not multithread safe but we don't care */

  snprintf(timebuf, sizeof(timebuf), "%02d:%02d:%02d.%06ld",

           now->tm_hour, now->tm_min, now->tm_sec, tv.tv_usec);

    (int)now->tm_hour, (int)now->tm_min, (int)now->tm_sec, (long)tv.tv_usec);

  va_start(ap, msg);

  vsprintf(buffer, msg, ap);

  vsnprintf(buffer, sizeof(buffer), msg, ap);

  va_end(ap);

  logfp = fopen(serverlogfile, "a");