fix alloc/free extent in undo log
  allow extent to be reused once a lcp is finished (instead of when next lcp starts)


storage/ndb/include/kernel/signaldata/Extent.hpp:
  Add lsn to alloc extent
storage/ndb/src/kernel/blocks/diskpage.hpp:
  Add (unused) undo entries for drop table, and alloc/free extent
storage/ndb/src/kernel/blocks/dblqh/DblqhMain.cpp:
  Notify TSMAN of both start and stop of LCP
storage/ndb/src/kernel/blocks/dbtup/Dbtup.hpp:
  1) Add unused undo entries for drop table, alloc/free extent
  2) handle create_table better (correct?) in undo log
  3) fix some typos/style
storage/ndb/src/kernel/blocks/dbtup/DbtupDiskAlloc.cpp:
  1) Add unused undo entries for drop table, alloc/free extent
  2) handle create_table better (correct?) in undo log
  3) fix some typos/style
storage/ndb/src/kernel/blocks/dbtup/DbtupExecQuery.cpp:
  fix style
storage/ndb/src/kernel/blocks/dbtup/DbtupGen.cpp:
  fix typo/style
storage/ndb/src/kernel/blocks/dbtup/DbtupMeta.cpp:
  Make sure regFragPtr.p->m_logfile_group_id = RNIL is applicable
storage/ndb/src/kernel/blocks/lgman.cpp:
  Add m_logfile_group_id to log callback
storage/ndb/src/kernel/blocks/print_file.cpp:
  Add (unused) undo entries for drop table, and alloc/free extent
storage/ndb/src/kernel/blocks/tsman.cpp:
  1) change so that LCP limit on resuse of extent is only for duration of lcp
  2) refactor so lookup_extent is put into subroutine
storage/ndb/src/kernel/blocks/tsman.hpp:
  refactor so lookup_extent is put into subroutine