Calling request() twice on the same client configured to connect to a
server via HTTPS didn't work under Unix because we issues CONNECT for
every request, meaning that, for the second one, we sent CONNECT via an
already established connection to the end server itself which,
unsurprisingly, didn't work at all.

Fix this by only setting up SSL tunnelling for a new connection but not
for the already used one.

…euse

# Conflicts:
#	Release/src/http/client/http_client_asio.cpp