lxclock: use XDG_RUNTIME_DIR for lock if appropriate (v2)
lxclock: use XDG_RUNTIME_DIR for lock if appropriate (v2)

If we are euid==0 or XDG_RUNTIME_DIR is not set, then use
/run/lock/lxc/$lxcpath/$lxcname as before.  Otherwise,
use $XDG_RUNTIME_DIR/lock/lxc/$lxcpath/$lxcname.

Signed-off-by: Serge Hallyn <3df611b026e4639bee8aef7a4beb2e39fcebb313@ubuntu.com>
Cc: Stéphane Graber <e63e941dc681603534cbbf85e7b402e46f0bf39d@canonical.com>
Acked-by: Stéphane Graber <089afc6d81f66f1168a9849e15660feae286e024@ubuntu.com>

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