cgmanager: cgm_get: len = 0 is a query for length only
cgmanager: cgm_get: len = 0 is a query for length only

The caller might (like lxc-test-startone does) pass in a valid
(or invalid) buffer and 0 length.

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

ojkastl/lxc_Patches,ojkastl/lxc_Patches,ojkastl/lxc_Patches,ojkastl/lxc_Patches