vzmigrate: detect "can't lock CT" error

In some cases we can't lock container not because it's already locked,
but for some other reason (running as non-root, no lock directory).

In such cases, there is no lock file, so we can check for this condition
print an appropriate error message and exit.

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