lxc-alpine: copy /etc/TZ to container if present

Signed-off-by: Kaarle Ritvanen <kaarle.ritvanen@datakunkku.fi>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>
lxcapi_clone: exit early on snapshot clones

If the user explicitly asks for a snapshot clone (in which
case maybe_snap is not set), we cannot abide this currently.
Rather than exit later with more cryptic error messages, exit
out early.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>