Do not send SMB2 signatures for SMB3 frames

Restructure code to make SMB2 vs. SMB3 signing a protocol
specific op.  SMB3 signing (AES_CMAC) is not enabled yet,
but this restructuring at least makes sure we don't send
an smb2 signature on an smb3 signed connection. A followon
patch will add AES_CMAC and enable smb3 signing.

Signed-off-by: Steve French <smfrench@gmail.com>
Acked-by: Jeff Layton <jlayton@samba.org>
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 290c134..f327623 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -1085,7 +1085,7 @@
 		vol->vals = &smb21_values;
 		break;
 	case Smb_30:
-		vol->ops = &smb21_operations; /* currently identical with 2.1 */
+		vol->ops = &smb30_operations;
 		vol->vals = &smb30_values;
 		break;
 #endif