so I commit again in a fresh tree.
Fix for bug#763 (Relay_log_space too big by 4 bytes),
plus comments and DBUG_PRINT, and we don't start replication
if --bootstrap.


mysql-test/r/rpl_log.result:
  Result update
mysql-test/r/rpl_log_pos.result:
  Result update
sql/mysqld.cc:
  Don't start replication if in bootstrap mode (bootstrap isn't supposed to have
  several threads).
sql/slave.cc:
  Fix for bug 763 (Relay_log_space too big by 4 bytes).
  A DBUG_PRINT.
sql/sql_acl.cc:
  Replaced a return by DBUG_RETURN (happened to find this reading a debug log).
sql/sql_repl.cc:
  A comment.