SSL: fixed ngx_ssl_recv() to reset c->read->ready after errors. With this change, behaviour of ngx_ssl_recv() now matches ngx_unix_recv(), which used to always reset c->read->ready to 0 when returning errors. This fixes an infinite loop in unbuffered SSL proxying if writing to the client is blocked and an SSL error happens (ticket #2418). With this change, the fix for a similar issue in the stream module (6868:ee3645078759), which used a different approach of explicitly testing c->read->error instead, is no longer needed and was reverted.