pgsql: Remove useless LIMIT_OPTION_DEFAULT value from LimitOption

Remove useless LIMIT_OPTION_DEFAULT value from LimitOption

During the development that led to commit 357889eb17bb, for a time we
had the value LIMIT_OPTION_DEFAULT, which was mostly but not completely
removed later on, before commit.  Complete the removal now.

Author: Zhang Mingli <avamingli@gmail.com>
Discussion: https://postgr.es/m/59d61a1a-3858-475a-964f-24468c97cc67@Spark

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/a6be0600ac3b71dda8277ab0fcbe59ee101ac1ce

Modified Files
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src/backend/parser/gram.y | 2 +-
src/include/nodes/nodes.h | 1 -
2 files changed, 1 insertion(+), 2 deletions(-)