and SET TRANSACTION READ ONLT|READ WRITE
statements.


per-file comments:
  mysql-test/include/check-warnings.test
        READ ONLY transaction flag cleaned.
  mysql-test/r/commit.result
        result updated
  mysql-test/r/read_only.result
        result updated
  mysql-test/t/commit.test
        tests added.
  mysql-test/t/read_only.test
        tests added
  sql/lex.h
        ONLY symbol added.
  sql/sql_base.cc
        DBUG_RETURN added.
  sql/sql_parse.cc
        implementations added.
  sql/sql_yacc.yy
        SQL syntax extended.
  storage/perfschema/gen_pfs_lex_token
        changes forced by lex.h
  storage/perfschema/pfs_lex_token.h
        changes forced by lex.h