plugins: Drop log plugin

Not yet implemented

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
plugins: std -- Shrink size of init args

No need for big chunk here, and rename it to init,
since arguments for plugins will be passed with
shmem plugin.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>