daemon/setMounts(): do not make /dev/shm ro
It has been pointed out that if --read-only flag is given, /dev/shm
also becomes read-only in case of --ipc private.
This happens because in this case the mount comes from OCI spec
(since commit 7120976d74195), and is a regression caused by that
commit.
The meaning of --read-only flag is to only have a "main" container
filesystem read-only, not the auxiliary stuff (that includes /dev/shm,
other mounts and volumes, --tmpfs, /proc, /dev and so on).
So, let's make sure /dev/shm that comes from OCI spec is not made
read-only.
Fixes: 7120976d74195 ("Implement none, private, and shareable ipc modes")
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>