Fix unused variable compiler warning in !debug builds.

Introduced in 3dbb317d.  Fix by using the new local variable in more
places.

Reported-By: Bruce Momjian (off-list)
Backpatch: 9.4-, like 3dbb317d

src/backend/catalog/indexing.c

@@ -154,12 +154,12 @@ CatalogIndexInsert(CatalogIndexState indstate, HeapTuple heapTuple)
 		/*
 		 * The index AM does the rest.
 		 */
-		index_insert(relationDescs[i],	/* index relation */
+		index_insert(index,		/* index relation */
 					 values,	/* array of index Datums */
 					 isnull,	/* is-null flags */
 					 &(heapTuple->t_self),	/* tid of heap tuple */
 					 heapRelation,
-					 relationDescs[i]->rd_index->indisunique ?
+					 index->rd_index->indisunique ?
 					 UNIQUE_CHECK_YES : UNIQUE_CHECK_NO,
 					 indexInfo);
 	}