vpnc-script adds an invalid route to Windows routing table

[d3cxxxx]

Describe the bug
When the server uses split tunnel to only route one endpoint (or a different subnet) through the tunnel, the vpnc script sets up a route using the tunnel address with its last octet incremented by one.
I only tested this on a windows server, so can't say the same about other platforms.

To Reproduce
Steps to reproduce the behavior:

1. In a windows server, install openconnect-gui 1.5.3.
2. Connect to a Cisco VPN server which will use split tunnel and provide one or more endpoint addresses (or subnets) that are different than the subnet from which the tunnel address is assigned.
3. Try to ping the endpoint.

Expected behavior
The ping should receive a response (assuming no firewall is blocking ICMP packets)

Screenshots
-None. Will add later if needed.

Desktop (please complete the following information):

• OS: Windows Server 2012 R2
• Browser: NA
• Version: 1.5.3 (openconnect-gui)

Additional context
If the tunnel address is 192.168.1.10, and the end point is 10.1.2.30, the route command used is:
route add 10.1.2.30 192.168.1.11