This changeset/patch is on top of changesets 1.1814 and 1.1846 
(for bugs 8033 and 8065) and now fixes bug 8535.

These changes have been built and tested successfully on build.mysql.com

handler.cc:
  Added hooks for federated_db_init() and federated_db_end(), 
  as done with ha_archive_db does, per suggestion by Ingo in
  code review of patch 1.1846.
ha_federated.h:
  declaration of federated_db_init() and federated_db_end()
ha_federated.cc:
  - Fixed some indentation problems from indent-ex (mainly to do with
    cases where "variablename += value"
  - Added federated_db_init() and federated_db_end(), as done with
    archive, which also handler more elegantly one of the memory leaks
    from bug 8033 where the federated_mutex was not freed
  - Removed extrenous debug messages in parse_url()
  - Fixed bug 8535, caused by NULL being quoted in write_row. This used to
    work (incorrectly) but a recent change was made in the server that 
    exposed this


sql/ha_federated.cc:
   - Fixed some indentation problems from indent-ex (mainly to do with
      cases where "variablename += value"
    - Added federated_db_init() and federated_db_end(), as done with
      archive, which also handler more elegantly one of the memory leaks
      from bug 8033 where the federated_mutex was not freed
    - Removed extrenous debug messages in parse_url()
sql/ha_federated.h:
  declaration of federated_db_init() and federated_db_end()
sql/handler.cc:
  Added hooks for federated_db_init() and federated_db_end(), as done with ha_archive_db does.