Fixed a bug in Aria when two threads was inserting into the same table and row page and one thread did an abort becasue of duplicate key.



mysys/thr_lock.c:
  Fixed valgrind warning
sql/sql_base.cc:
  Remove not used variable
storage/maria/ma_bitmap.c:
  Added ma_bitmap_lock() & ma_bitmap_unlock() to protect against two threads using the bitmap at the same time.
  More DBUG_PRINT()
storage/maria/ma_blockrec.c:
  Fixed a bug in Aria when two threads was inserting into the same table and row page and one thread did an abort becasue of duplicate key.
  Fix was that we block other threads to modify the bitmap while we are removing the row with a duplicate key.
storage/maria/ma_blockrec.h:
  Added ma_bitmap_lock() & ma_bitmap_unlock() to protect against two threads using the bitmap at the same time.
storage/maria/maria_def.h:
  Changed flush_all_requested to be a counter.
storage/myisam/mi_locking.c:
  Fixed compiler error on windows (typo).