camera: Wait for continous focus to complete before taking a picture

Signed-off-by: Paul Kocialkowski <contact@paulk.fr>
Change-Id: I2aef0e3e413c9a8708fe1c87860beb287c844a1c
(cherry picked from commit 39a1ebdfea1a37d01f9c382b98cfd48a96e98184)