db_oracle: fix warning: passing argument 2 of ‘db_do_close’ from incompatible pointer type [-Wincompatible-pointer-types]

(cherry picked from commit 577a87861a8566e00f2700dfb227dcc8b26393b4)

src/modules/db_oracle/dbase.c

@@ -176,7 +176,7 @@ db1_con_t *db_oracle_init(const str *_url)
  */
 void db_oracle_close(db1_con_t *_h)
 {
-	db_do_close(_h, db_oracle_free_connection);
+	db_do_close(_h, (void *)db_oracle_free_connection);
 }