Removed defunct track_branches option in emubd

bd/lfs_emubd.h

@@ -94,10 +94,6 @@ struct lfs_emubd_config {
     // Data for power-loss callback
     void *powerloss_data;
 
-    // True to track when power-loss could have occured. Note this involves 
-    // heavy memory usage!
-    bool track_branches;
-
     // Path to file to use as a mirror of the disk. This provides a way to view
     // the current state of the block device.
     const char *disk_path;