GlobalProtect: try to connect to portal interface before gateway
GlobalProtect: try to connect to portal interface before gateway

This makes OpenConnect behave more like the official GP clients, which
should make more sense to new users especially when troublesheeting, without
removing the useful ability to connect directly to a gateway.
(See https://gitlab.com/openconnect/openconnect/merge_requests/56#note_209428777)

Signed-off-by: Daniel Lenski <e5bace4159f0f869e01725c5a04427ee0a92b09d@gmail.com>

brandt/openconnect,brandt/openconnect,brandt/openconnect,brandt/openconnect