By Natalie Thomas and Jonathan Saul ODESSA, Ukraine/LONDON (Reuters) – Black and white newsreel from 1941 shows residents of Odessa, then a Soviet city, building barricades with cobblestones, while the streets are lined with sandbag defences and “hedgehog” anti-tank barriers as German and Romanian forces approach. Fast forward 81 years, and similar scenes are playing out in the picturesque Black Sea port, this time with Ukrainians hurrying to prepare Odessa for a possible assault by Russian troops by land, sea or both. Military experts said an attempt to capture Odessa, which has so far been s…