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_4_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/f304ddc5cefff167e702c044269d75df2d5b4508

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