pgsql: Fix obsolete mention of non-int64 support in CREATE SEQUENCE doc

Fix obsolete mention of non-int64 support in CREATE SEQUENCE documentation.

The old text explained what happened if we didn't have working int64
arithmetic.  Since that case has been explicitly rejected by configure
since 8.4.3, documenting it in the 9.x branches can only produce confusion.

Branch
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REL9_1_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/5f1c5970765aad9b25ff50403065c54d3ebc37e6

Modified Files
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doc/src/sgml/ref/create_sequence.sgml |    5 +----
1 file changed, 1 insertion(+), 4 deletions(-)