oncp_control_queue → tcp_control_queue

oncp_control_queue → tcp_control_queue

This is a queue for outgoing packets which must be sent over the
TCP-based transport; that is, they cannot be sent over the
UDP-based transport.

This queue was initially used by oNCP protocol for ESP enable/disable
packets, and it is now also used by Pulse. It will likely be used for
control packets by some PPP-based protocols as well.

Renaming it to TCP control queue to emphasize its cross-protocol
nature (cf. https://gitlab.com/openconnect/openconnect/-/merge_requests/151).

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