fix sshd template

Commit a0a2066d introduced an lxc subdir into the lxc-init path, but
this was never reflected in the sshd template. Add it there.

Don't have ssh-keygen ask for passphrase since host keys are not
supposed to use them.

Don't try to symlink kmsg since /dev is bind mounted readonly.

Read-only bind mount some extra /etc directories, and sysfs which are
needed by dhclient on Fedora and Oracle Linux. Fix mounting of /proc.

Find sshd in more places by adding some common paths to $PATH, and
use the found path to it instead of hardcoded /usr/sbin.

Check for ifconfig command, and print out container's IP address.

Signed-off-by: Dwight Engen <dwight.engen@oracle.com>
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>