pgsql: Fix -Wcast-qual warning

Fix -Wcast-qual warning

This dials back a couple of the qualifiers added by commit
7724cb9935a.  Specifically, in match_boolean_partition_clause() the
call to negate_clause() casts away the const, so we shouldn't make the
input argument const.

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/119e791e9c7d7d122f7a9554514455c38115964a

Modified Files
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src/backend/partitioning/partprune.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)