pgsql: Set user_defined_types.data_type to null

Set user_defined_types.data_type to null

On re-reading the standard, this field is only used for distinct or
reference types.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/6fbc80349f601dc32f38b89a997913ea684b9f32

Modified Files
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doc/src/sgml/information_schema.sgml       |    6 +-----
src/backend/catalog/information_schema.sql |    2 +-
2 files changed, 2 insertions(+), 6 deletions(-)