Docker: Add network inactivity timeout to docker operations
Docker: Add network inactivity timeout to docker operations

Before, pulling docker images could stall the thread indefinitely if the
pull was somehow interrupted. Pull operations now error in the case of
extended network inactivity.

tejasmanohar/quilt,NetSys/quilt,mmussomele/quilt,NetSys/quilt,mmussomele/quilt,kklin/kelda,kayousterhout/quilt,mmussomele/quilt,PenguinToast/quilt,kayousterhout/quilt,mmussomele/quilt,NetSys/quilt,quilt/quilt,stevenlin598/quilt,quilt/quilt,stevenlin598/quilt,kelda/kelda,mmussomele/quilt,kayousterhout/quilt,LuiseV/quilt,kayousterhout/quilt,kklin/quilt,PenguinToast/quilt,kelda/kelda,LuiseV/quilt,stevenlin598/quilt,PenguinToast/quilt,kklin/kelda,ejj/quilt-dev,tejasmanohar/quilt,LuiseV/quilt,tejasmanohar/quilt,tejasmanohar/quilt,kklin/kelda,quilt/quilt,ejj/quilt-dev,NetSys/quilt,PenguinToast/quilt,kklin/quilt,kklin/quilt,LuiseV/quilt,LuiseV/quilt,kklin/quilt,kelda/kelda,ejj/quilt-dev,PenguinToast/quilt,mmussomele/quilt,NetSys/quilt,stevenlin598/quilt,kklin/kelda,stevenlin598/quilt,stevenlin598/quilt,ejj/quilt-dev,kelda/kelda,quilt/quilt