Update container resolv.conf when host network changes /etc/resolv.conf

Only modifies non-running containers resolv.conf bind mount, and only if
the container user has not modified the original resolv.conf at
container start time (so we don't overwrite manual/automated changes
within the container runtime).

Docker-DCO-1.1-Signed-off-by: Phil Estes <estesp@linux.vnet.ibm.com> (github: estesp)