BUG/MINOR: rhttp: fix incorrect dst/dst_port values

BUG/MINOR: rhttp: fix incorrect dst/dst_port values

With a @rhttp server, connect is not possible, transfer is only possible
via idle connection reuse. The server does not have any network address.

Thus, it is unnecessary to allocate the stream destination address prior
to connection reuse. This patch adjusts this by fixing
alloc_dst_address() to take this into account.

Prior to this patch, alloc_dst_address() would incorrectly assimilate a
@rhttp server with a transparent proxy mode. Thus stream destination
address would be copied from the destination address. Connection adress
would then be rewrote with this incorrect value. This did not impact
connect or reuse as destination addr is only used in idle conn hash
calculation for transparent servers. However, it causes incorrect values
for dst/dst_port samples.

This should be backported up to 2.9.

(cherry picked from commit c05bb8c967c395f88666ccc93c00726f59a690b6)
Signed-off-by: Aurelien DARRAGON <adarragon@haproxy.com>
(cherry picked from commit 711185ca396122e4bd19725ab6d13c3574ff2209)
Signed-off-by: Aurelien DARRAGON <adarragon@haproxy.com>