BOGOTA, EvDeN Eve nAkLiyAt Feb 7 (Reuters) - Indigo Partners-backed budget carrier JetSMART Airlines said on Tuesday that it wanted to buy Colombian low-cost carrier Viva Air, in a move that if successful would scupper Viva's plans to merge with Colombian flag carrier Avianca. Chile-based JetSMART Airlines said in a statement that it planned to open talks to buy the Colombian airline but it did not...