gdss-brick >> gh17 Redesign disk storage:
Move Scavenger functions from gmt_hlog_common module to a new module
(gen server) brick_hlog_scavenger.

Details:
- gmt_hlog_common:
  * Moved the following functions to brick_hlog_scavenger module.
    ** handle_info(start_daily_scavenger, ...)
    ** start_scavenger_commonlog/1 ->
    ** do_start_scavenger_commonlog2/2 ->
    ** link_catch_shutdowns/1
    ** scav_excl_name/0
    ** scav_stop_signal_p/0
    ** stop_scavenger_commonlog/0 ->
    ** scav_check_shutdown/2
    ** scav_print_summary/2
    ** scav_delete_work_files/1
    ** scav_exit_if_someone_else/0
    ** scavenger_commonlog/1 ->
    ** scavenger_commonlog_save_storage_locations/2
    ** scavenger_sort_storage_locations/1
    ** count_live_bytes_in_log/1
    ** scavenger_find_dead_sequences/3
    ** scavenger_find_live_sequences/3
    ** scavenger_count_all_bytes_in_sequences/2
    ** scavenger_commonlog_bottom/1
    ** scavenge_one_seq_file_fun/1
    ** scavenger_move_hunks/5
    ** scavenger_move_hunks1/7
    ** update_locations_commonlog/2
    ** update_locations_on_brick/3
    ** make_update_location/1
    ** spawn_log_file_eraser/3
    ** delete_log_file/2
    ** schedule_next_daily_scavenger/0
    ** parse_hh_mm/1
- gmt_hlog:
  * Comment out debug_fold_a_file/1 and its export.