backout r1757, we really need SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER

src/event/ngx_event_openssl.c

diff --git a/src/event/ngx_event_openssl.c b/src/event/ngx_event_openssl.c
index edbb16f..0c8b9d8 100644
--- a/src/event/ngx_event_openssl.c
+++ b/src/event/ngx_event_openssl.c
@@ -187,6 +187,13 @@
         SSL_CTX_set_options(ssl->ctx, ngx_ssl_protocols[protocols >> 1]);
     }
 
+    /*
+     * we need this option because in ngx_ssl_send_chain()
+     * we may switch to a buffered write and may copy leftover part of
+     * previously unbuffered data to our internal buffer
+     */
+    SSL_CTX_set_mode(ssl->ctx, SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER);
+
     SSL_CTX_set_read_ahead(ssl->ctx, 1);
 
     return NGX_OK;