Fix fallback to passthrough when no cert present

Properly reset connection state when reconnecting the dst part of the
connection.  This fixes the fallback to passthrough when no certficates
are present which can be used to split the SSL.

Issue:          #9
Reported by:    ceear

pxyconn.c

@@ -1276,8 +1276,10 @@ pxy_bev_eventcb(struct bufferevent *bev, short events, void *arg)
 			ctx->src.ssl = pxy_srcssl_create(ctx, this->ssl);
 			if (!ctx->src.ssl) {
 				bufferevent_free_and_close_fd(bev, ctx);
+				ctx->dst.ssl = NULL;
 				if (ctx->opts->passthrough && !ctx->enomem) {
 					ctx->passthrough = 1;
+					ctx->connected = 0;
 					log_dbg_printf("No cert found; "
 					               "falling back "
 					               "to passthrough\n");