smb3: fix lease break problem introduced by compounding

Fixes problem (discovered by Aurelien) introduced by recent commit:
commit b24df3e3
("cifs: update receive_encrypted_standard to handle compounded responses")

which broke the ability to respond to some lease breaks
(lease breaks being ignored is a problem since can block
server response for duration of the lease break timeout).
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>

fs/cifs/connect.c

@@ -946,8 +946,7 @@ cifs_demultiplex_thread(void *p)
 		} else {
 			mids[0] = server->ops->find_mid(server, buf);
 			bufs[0] = buf;
-			if (mids[0])
-				num_mids = 1;
+			num_mids = 1;
 
 			if (!mids[0] || !mids[0]->receive)
 				length = standard_receive3(server, mids[0]);