This change uses the reexec package to run the update of the
ldcache in a container in a process with isolated namespaces.
Since the hook is invoked as a createContainer hook, these
namespaces are cloned from the container's namespaces.
In the reexec handler, we further isolate the proc filesystem,
mount the host ldconfig to a tmpfs, and pivot into the containers
root.
Signed-off-by: Evan Lezar <elezar@nvidia.com>
