MEDIUM: config: replace ssl_conf by bind_conf

Some settings need to be merged per-bind config line and are not necessarily
SSL-specific. It becomes quite inconvenient to have this ssl_conf SSL-specific,
so let's replace it with something more generic.
diff --git a/src/proxy.c b/src/proxy.c
index 56d343e..307af93 100644
--- a/src/proxy.c
+++ b/src/proxy.c
@@ -443,7 +443,7 @@
 	LIST_INIT(&p->logsrvs);
 	LIST_INIT(&p->logformat);
 	LIST_INIT(&p->format_unique_id);
-	LIST_INIT(&p->conf.ssl_bind);
+	LIST_INIT(&p->conf.bind);
 
 	/* Timeouts are defined as -1 */
 	proxy_reset_timeouts(p);