Some cases can cause the server initialization to block (namely running
a 2nd containerd instance by accident against the same root dir). In
this case there is no way to quit the daemon except with `kill -9`.
This changes context things so that server init is done in a goroutine
and we wait on a channel for it to be ready while we also wait for a
ctx.Done(), which will be cancelled if there is a termination signal.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>