vzmigrate: fix 'if' statement

Commit ebd5fb00a4eb0134d7ef4ebfdc0b6ae43d07d8fd breaks one 'if' expression,
leading to the following error:

   /usr/sbin/vzmigrate: line 382: [: missing `]'

Fix it.

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