remove biglock usage from ipsectunnel.sh

Biglock breaks creating VPN's when other scripts run at the
same time that also use the same biglock. These other scripts
do nothing that could harm our deployment and even multiple
vpn's can safely be created simultaniously.

(cherry picked from commit 8b412ce194eaf195dc77531379687de43e14a088)
renamed $leftgw to $leftnexthop to make clear what it does

(cherry picked from commit 8b2563a216b012ab1905e65f446c8b6b1435b983)
starting the tunnel will make it keep trying until it connects

Changed 'auto=add' to 'auto=start' to make sure the tunnel starts.
When both sides are there they will connect. This resolves the
issue that there is only a small time frame in which the VPN
would connect.

(cherry picked from commit b95addd3efb45f61b129584ade49bad7bbaa16f8)