pgsql: More sensible character_octet_length For character types with

Log Message:
-----------
More sensible character_octet_length

For character types with typmod, character_octet_length columns in the
information schema now show the maximum character length times the
maximum length of a character in the server encoding, instead of some
huge value as before.

Modified Files:
--------------
    pgsql/doc/src/sgml:
        information_schema.sgml (r1.39 -> r1.40)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/information_schema.sgml?r1=1.39&r2=1.40)
    pgsql/src/backend/catalog:
        information_schema.sql (r1.54 -> r1.55)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/catalog/information_schema.sql?r1=1.54&r2=1.55)
    pgsql/src/backend/utils/mb:
        mbutils.c (r1.87 -> r1.88)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/mb/mbutils.c?r1=1.87&r2=1.88)
    pgsql/src/include/catalog:
        catversion.h (r1.531 -> r1.532)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/catversion.h?r1=1.531&r2=1.532)
        pg_proc.h (r1.544 -> r1.545)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/pg_proc.h?r1=1.544&r2=1.545)
    pgsql/src/include/utils:
        builtins.h (r1.332 -> r1.333)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/utils/builtins.h?r1=1.332&r2=1.333)