LXC TEMPLATE WILL CREATE MOUNT

Lxc driver was throwing errors for mounts where the mount point does not exist in the container.
This adds a create=dir/file mount option to the lxc template, to alleviate this issue.

Docker-DCO-1.1-Signed-off-by: Abin Shahab <ashahab@altiscale.com> (github: ashahab-altiscale)
you can get the stat directly with `os.Stat(source)` without opening closing the source: http://golang.org/pkg/os/#Stat. You can still check whether the directory exists or not with less code :smile: