Before this commit, adding multiple options to a bind-type mount
(e.g. /foo/bar:/baz:Z,U) would result in a podman command in which
only the last option would be used (e.g. U).
This is because when parsing the mount string, a loop would go over
each mount option and assign it to mount_opt_dict, this meant that
this dict was overridden for each option, thus only the last option
in the mount string would be kept and passed onto podman.
This commit solves this by appending to a temporary list and then
converting it to a comma-separated string and assigning it to the
mount_opt_dict.
Fixes#412
Signed-off-by: Adrian Torres <atorresj@redhat.com>
