SPDY: fixed connection leak while waiting for request body. If an error occurs in a SPDY connection, the c->error flag is set on every fake request connection, and its read or write event handler is called, in order to finalize it. But while waiting for a request body, it was a no-op since the read event handler ngx_http_request_handler() calls r->read_event_handler that had been set to ngx_http_block_reading().