pgsql: Fix incorrect encoding-aware name truncation in

Log Message:
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Fix incorrect encoding-aware name truncation in makeArrayTypeName().

truncate_identifier won't do anything if the passed-in strlen is already
less than NAMEDATALEN, which it always would be given the strlcpy usage.
This has been broken since the arrays-of-composite-types code went in.

Arguably truncate_identifier is suffering from excessive optimization
and should always process the string, but for the moment I'll take the
more localized patch.

Per bug #4987.

Tags:
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REL8_4_STABLE

Modified Files:
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pgsql/src/backend/catalog:
pg_type.c (r1.126 -> r1.126.2.1)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/catalog/pg_type.c?r1=1.126&r2=1.126.2.1)