[SCSI] iscsi_tcp: fix header resend

This patch built over the last ones fixes a bug in the partial header
resend code, where we add on another 4 bytes to the send length on the resend.
We want just the header plus digest.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

drivers/scsi/iscsi_tcp.c

@@ -109,7 +109,7 @@ iscsi_hdr_digest(struct iscsi_conn *conn, struct iscsi_buf *buf,
 	struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 
 	crypto_digest_digest(tcp_conn->tx_tfm, &buf->sg, 1, crc);
-	buf->sg.length += sizeof(uint32_t);
+	buf->sg.length = tcp_conn->hdr_size;
 }
 
 static inline int