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_2_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/ae941b8db49dc61a8d085a4fb6f1d5106ec40275

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