Editing an event with new attributes fails because a new id is not assigned correctly, fixes #773
Editing an event with new attributes fails because a new id is not assigned correctly, fixes #773

- the process of detecting and editing existing attributes did not account for a case where the uuid is not set for an attribute and therefore should be saved as a new attribute. Fixed

FloatingGhost/MISP,cristianbell/MISP,FIRSTdotorg/MISP,FloatingGhost/MISP,FIRSTdotorg/MISP,crruthe/MISP,RichieB2B/MISP,crruthe/MISP,SteveClement/MISP,crruthe/MISP,TheDr1ver/MISP,cristianbell/MISP,FloatingGhost/MISP,MISP/MISP,FIRSTdotorg/MISP,devnull-/MISP,Rafiot/MISP,MISP/MISP,SteveClement/MISP,RichieB2B/MISP,FloatingGhost/MISP,devnull-/MISP,RichieB2B/MISP,Rafiot/MISP,RichieB2B/MISP,TheDr1ver/MISP,TheDr1ver/MISP,Rafiot/MISP,devnull-/MISP,TheDr1ver/MISP,cristianbell/MISP,cristianbell/MISP,FIRSTdotorg/MISP,MISP/MISP,MISP/MISP,SteveClement/MISP,SteveClement/MISP,crruthe/MISP,MISP/MISP,SteveClement/MISP,Rafiot/MISP,devnull-/MISP