Don't backup the dsts.ini file when saving changes, not needed any more

Root-caused this problem to read() failures which are now caught and logged
rather than zeroing out the statistics fields.

src/sbbs3/getstats.c

@@ -70,10 +70,6 @@ FILE* fopen_dstats(scfg_t* cfg, uint node, bool for_write)
     char path[MAX_PATH+1];
 
 	dstats_fname(cfg, node, path, sizeof(path));
-#ifdef _DEBUG
-	if(for_write)
-		backup(path, 99, /* rename: */false);
-#endif
 	return fnopen(NULL, path, for_write ? O_CREAT|O_RDWR : O_RDONLY);
 }