Review fixes for #1570 and #1650
Review fixes for #1570 and #1650

Try to increase readability of vy_apply_upsert().

rtsisyk/tarantool,mejedi/tarantool,mejedi/tarantool,rtsisyk/tarantool,mejedi/tarantool,rtsisyk/tarantool,mejedi/tarantool,rtsisyk/tarantool