fix ndb-violations of strict aliasing found by gcc4.1
  (crashes in ndb_dd_*)


storage/ndb/src/kernel/blocks/dbdict/Dbdict.cpp:
  Fix strict-aliasing
storage/ndb/src/kernel/vm/KeyTable2Ref.hpp:
  Fix strict-aliasing
storage/ndb/src/kernel/vm/Pool.hpp:
  Fix strict-aliasing