PPTP: fix condition of killing existing connections
PPTP: fix condition of killing existing connections

The assigned IP address is not in the commandline parameters, in this
case we cannot filter the process by the IP address.

Fixes: 9aa0b4358 ("PPTP: kill existing connections more carefully")
Fixes: redmine #11087

Signed-off-by: Hunt Xu <0e5338760d0f239687243393e6a20f88a8f69100@gmail.com>

eayunstack/eayunstack-upgrade,eayunstack/eayunstack-upgrade,eayunstack/eayunstack-upgrade,huntxu/eayunstack-upgrade,eayunstack/eayunstack-upgrade,huntxu/eayunstack-upgrade,huntxu/eayunstack-upgrade,huntxu/eayunstack-upgrade