(char_table_open_db_maybe): Defined even if `CHISE' is not defined;
add code for non-libchise setting.
(char_table_close_db_maybe): Likewise.
(char_table_get_db): New function when `HAVE_CHISE_CLIENT' is defined.
(Fclose_char_attribute_table): Use `char_table_close_db_maybe' even if
`CHISE' is not defined.
(Freset_char_attribute_table): Likewise.
(load_char_attribute_maybe): Use `char_table_open_db_maybe' and
`char_table_close_db_maybe' even if `CHISE' is not defined; use
`char_table_get_db'.
(Fload_char_attribute_table): Use `char_table_open_db_maybe' and
`char_table_close_db_maybe' even if `CHISE' is not defined.