remove old junk and to improve compression ratio.
InnoDB: Make implicit type conversions explicit. (Bug #8826)


innobase/btr/btr0cur.c:
  Add "offsets" parameter to page_cur_delete_rec() calls
  btr_cur_optimistic_delete(): Simplify the logic with a flag variable
  btr_cur_pessimistic_delete(): Compute "offsets" earlier
innobase/include/page0cur.h:
  page_cur_delete_rec(): Add parameter "offsets"
innobase/include/page0page.h:
  page_mem_free(): Replace parameter "index" with "offsets"
innobase/include/page0page.ic:
  page_mem_free(): Replace parameter "index" with "offsets".
  Clear the data bytes of the freed record.
  (The "extra" bytes will be needed by free space management.)
innobase/include/rem0rec.h:
  Remove unnecessary function rec_get_size()
innobase/log/log0recv.c:
  Remove function rec_apply_log_recs_for_backup()
  unless #ifdef UNIV_HOTBACKUP.
innobase/page/page0cur.c:
  Add parameter "offsets" to page_cur_delete_rec().
innobase/page/page0page.c:
  page_create(): Zero fill the data area.
  page_delete_rec_list_start(): Add parameter "offsets"
  to page_cur_delete_rec().
innobase/rem/rem0rec.c:
  Remove unnecessary function rec_get_size().
  Fix compiler warnings about implicit type conversions.  (Bug #8826)
innobase/srv/srv0srv.c:
  Fix compiler warnings about implicit type conversions. (Bug #8826)
innobase/sync/sync0sync.c:
  Fix compiler warnings about implicit type conversions. (Bug #8826)