lib/net.c: fix dcachesize/kmemsize leak on --netdev_del

1. There should be no fork()/setluid() performed on VE_NETDEV_DEL,
otherwise a few sysctl entries will be pinned to CT's beancounters.
This should fix dcachesize/kmemsize leak on --netdev_del.

2. There is no need to do setublimit(), and there is no need to do
fork() after setluid(). This simplifies the code a lot.

3. Fix a logger() statement: errors come with log level of -1.

Issue PSBM-7272.

Signed-off-by: Kir Kolyshkin <kir@openvz.org>
1 file changed