Display warning when connecting to compressing server with compression disabled in client

[cycloon]

OpenVPN Connect on iOS currently disables compression as default. Given VORACLE that seems reasonable to me.

When connecting to a community server that uses and pushes compression you get a connection that seems to work. You can even ping through that tunnel. But if you do pretty much anything else, the tunnel does not work because the client does not compress.

To find out what is wrong, you have to stumble on one of these URLs:
​https://forums.openvpn.net/viewtopic.php?f=36&t=27195
​https://community.openvpn.net/openvpn/ticket/1126
​https://community.openvpn.net/openvpn/wiki/VORACLE

Of course that happens after some hours of debugging, tracing on server side and on client side.

Please considere the following Change Request:
Upon connecting to a server that uses compression or pushes compression via push "compress lz4-v2" display a warning to the user and write the same warning something to the log