This change allows containers to mount and remount volumes as needed.
Before this change, when users had a mounted volume within a container,
like in the case of services using NFS or RBD, it was not possible to
remount a volume within the container runtime. While a user could
unmount and mount a volume or restart a container, these actions
results in service interuption where as a remount would simply
reload the mounted volume without service interuption.
Change-Id: Iff588cad451320167b92f2d79e4693a1037be966
Closes-Bug: #1814200
Signed-off-by: cloudnull <kevin@cloudnull.com>