Remove a unused argument from qual_is_pushdown_safe

[Yugo NAGATA]

Hello,

I found that qual_is_pushdown_safe() has an argument "subquery"
that is not used in the function.  This argument has not been
referred to since the commit 964c0d0f80e485dd3a4073e073ddfd9bfdda90b2.

I think we can remove this if there is no special reason. 

Regards,
Yugo Nagata 

-- 
Yugo NAGATA <nag...@sraoss.co.jp>

diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c
index 4ddaed31a4..5327ea2803 100644
--- a/src/backend/optimizer/path/allpaths.c
+++ b/src/backend/optimizer/path/allpaths.c
@@ -136,8 +136,7 @@ static void check_output_expressions(Query *subquery,
 static void compare_tlist_datatypes(List *tlist, List *colTypes,
 									pushdown_safety_info *safetyInfo);
 static bool targetIsInAllPartitionLists(TargetEntry *tle, Query *query);
-static bool qual_is_pushdown_safe(Query *subquery, Index rti,
-								  RestrictInfo *rinfo,
+static bool qual_is_pushdown_safe(Index rti, RestrictInfo *rinfo,
 								  pushdown_safety_info *safetyInfo);
 static void subquery_push_qual(Query *subquery,
 							   RangeTblEntry *rte, Index rti, Node *qual);
@@ -2527,7 +2526,7 @@ set_subquery_pathlist(PlannerInfo *root, RelOptInfo *rel,
 			Node	   *clause = (Node *) rinfo->clause;
 
 			if (!rinfo->pseudoconstant &&
-				qual_is_pushdown_safe(subquery, rti, rinfo, &safetyInfo))
+				qual_is_pushdown_safe(rti, rinfo, &safetyInfo))
 			{
 				/* Push it down */
 				subquery_push_qual(subquery, rte, rti, clause);
@@ -3813,7 +3812,7 @@ targetIsInAllPartitionLists(TargetEntry *tle, Query *query)
  * found to be unsafe to reference by subquery_is_pushdown_safe().
  */
 static bool
-qual_is_pushdown_safe(Query *subquery, Index rti, RestrictInfo *rinfo,
+qual_is_pushdown_safe(Index rti, RestrictInfo *rinfo,
 					  pushdown_safety_info *safetyInfo)
 {
 	bool		safe = true;