vzctl: fix removing IPv6 address from a VE

Without this patch, IPv6 address is not removed from a VE:

  # vzctl set <VEID> --ipdel fc00::1 --save
  Warning: ipv6 support disabled <---*
  Deleting IP address(es):
  Saved parameters for VE <VEID>

Thanks to Thorsten Schifferdecker for reporting the issue.

[kir@openvz.org: changelog, porting to latest git]
1 file changed