remove isDefined constraint on many functions
remove isDefined constraint on many functions

For all operations on running containers, allow them to run on containers with
no config file.

Destroy, snapshot, and clone do require the container to be defined
(which is enforced by the C api calls as well).

Signed-off-by: Serge Hallyn <3df611b026e4639bee8aef7a4beb2e39fcebb313@ubuntu.com>

virajs/go-lxc,anupcshan/go-lxc,anupcshan/go-lxc,virajs/go-lxc