Automatic primary key for BDB tables

sql/field.h:
  Cleanup
sql/filesort.cc:
  Cleanup
sql/opt_range.cc:
  Remove index in use
sql/sql_base.cc:
  Allow Berkeley DB tables used only the index when the query only uses
  the index + data from the primary key
sql/sql_select.cc:
  Fix for left join optimization
BitKeeper/etc/logging_ok:
  Logging to logging@openlogging.org accepted

sql/handler.h

@@ -202,6 +202,7 @@ public:
   virtual double read_time(ha_rows rows) { return rows; }
   virtual bool fast_key_read() { return 0;}
   virtual bool has_transactions(){ return 0;}
+  virtual uint extra_rec_buf_length() { return 0; }
 
   virtual int index_init(uint idx) { active_index=idx; return 0;}
   virtual int index_end() {return 0; }