* remove superflus mounts of /dev/null and /dev/urandom
* reset EXTRA_MOUNTS at the beginning of the script
* add mount according to ignore_hosts_dir
* don't add mount for file which is inside a directory already in the
EXTRA_MOUNTS list
Fixes: 59c63224e1 ("dnsmasq: rework jail mounts")
Reported-by: Hartmut Birr <e9hack@gmail.com>
Signed-off-by: Daniel Golle <daniel@makrotopia.org>