Incorporating changes from review.
Fixing one bug that surfaced.


mysql-test/extra/rpl_tests/rpl_row_tabledefs.test:
  Adding tests that UPDATE and DELETE does not generate an error.
mysql-test/r/rpl_row_tabledefs_2myisam.result:
  Result change.
mysql-test/r/rpl_row_tabledefs_3innodb.result:
  Result change.
mysql-test/t/disabled.def:
  Enabling rpl_sp_effects (even though it gives a result mismatch currently).
sql/field.cc:
  Using constant to denote undefined last null byte.
sql/field.h:
  Using constant to denote undefined last null byte.
  Adding documentation.
sql/log_event.cc:
  Not generating error for non-NULL no-DEFAULT columns when updating or deleting row.
  Better documentation and comments.
sql/rpl_utility.cc:
  Moving documentation to header file.
sql/rpl_utility.h:
  Documenting class and members.