redo checkSchemaState to handle bug (plus prepare to handle other DD related bugs in the area)


storage/ndb/src/kernel/blocks/dbdict/Dbdict.cpp:
  bug#21755
    redo checkSchemaState to handle bug (plus prepare to handle other DD related bugs in the area)
storage/ndb/src/kernel/blocks/dbdict/Dbdict.hpp:
  bug#21755