[CIFS] Fix oops when negotiating lanman and no password specified

Pointed out by Guenter Kukkukk

Signed-of-by: Steve French <sfrench@us.ibm.com>
(cherry picked from bbf33d512da608c7221fec42b56b9ef89c25a5ee commit)
diff --git a/fs/cifs/cifsencrypt.c b/fs/cifs/cifsencrypt.c
index a89efaf..4bc250b 100644
--- a/fs/cifs/cifsencrypt.c
+++ b/fs/cifs/cifsencrypt.c
@@ -277,7 +277,8 @@
 		return;
 
 	memset(password_with_pad, 0, CIFS_ENCPWD_SIZE);
-	strncpy(password_with_pad, ses->password, CIFS_ENCPWD_SIZE);
+	if(ses->password)
+		strncpy(password_with_pad, ses->password, CIFS_ENCPWD_SIZE);
 
 	if((ses->server->secMode & SECMODE_PW_ENCRYPT) == 0)
 		if(extended_security & CIFSSEC_MAY_PLNTXT) {