MINOR: remove the client/server side distinction in SI addresses

Stream interfaces used to distinguish between client and server addresses
because they were previously of different types (sockaddr_storage for the
client, sockaddr_in for the server). This is not the case anymore, and this
distinction is confusing at best and has caused a number of regressions to
be introduced in the process of converting everything to full-ipv6. We can
now remove this and have a much cleaner code.
diff --git a/src/session.c b/src/session.c
index d39da99..9c66906 100644
--- a/src/session.c
+++ b/src/session.c
@@ -96,7 +96,7 @@
 	LIST_INIT(&s->back_refs);
 
 	s->term_trace = 0;
-	s->si[0].addr.c.from = *addr;
+	s->si[0].addr.from = *addr;
 	s->logs.accept_date = date; /* user-visible date for logging */
 	s->logs.tv_accept = now;  /* corrected date for internal use */
 	s->uniq_id = totalconn;
@@ -278,8 +278,8 @@
 	fdtab[cfd].cb[DIR_RD].b = s->req;
 	fdtab[cfd].cb[DIR_WR].f = l->proto->write;
 	fdtab[cfd].cb[DIR_WR].b = s->rep;
-	fdinfo[cfd].peeraddr = (struct sockaddr *)&s->si[0].addr.c.from;
-	fdinfo[cfd].peerlen  = sizeof(s->si[0].addr.c.from);
+	fdinfo[cfd].peeraddr = (struct sockaddr *)&s->si[0].addr.from;
+	fdinfo[cfd].peerlen  = sizeof(s->si[0].addr.from);
 	EV_FD_SET(cfd, DIR_RD);
 
 	if (p->accept && (ret = p->accept(s)) <= 0) {