Avoid a potential build error and circular dependency by making
rootlesskit optional. Note that rootlesskit is still required in order
for rootless docker to function.
Signed-off-by: Kenton Groombridge <me@concord.sh>
Rootless docker runs as root in a user namespace. Because of this,
rootless docker containers will run as spc_user_t as docker cannot be
SELinux-aware in its own container.
Signed-off-by: Kenton Groombridge <me@concord.sh>