async: drop leftover get_next_answer
async: drop leftover get_next_answer

These always return None

Signed-off-by: Marc-Antoine Perennou <07f76cf0511c79b361712839686f3cee8c75791c@Perennou.com>

sozu-proxy/lapin,swizard0/lapin,Geal/lapin,swizard0/lapin,Geal/lapin