pgsql: Fix bool abuse

Fix bool abuse

path_encode's "closed" argument used to take three values: TRUE, FALSE,
or -1, while being of type bool.  Replace that with a three-valued enum
for more clarity.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/7888c61238ca082404cf8348a69e2b66bf9f4e96

Modified Files
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src/backend/utils/adt/geo_ops.c |   34 ++++++++++++++++++----------------
1 file changed, 18 insertions(+), 16 deletions(-)