CIFS allow all BACKUP_OPTIONS + Fix broken cryptsetup

Commit1:
CIFS: Fix cred option not detected + remove checking for cred options co...mpletely so that users are not stuck with the guest mount option when they want to use other then the cred cifs mount option. Only use guest option by default when no other BACKUP_OPTIONS are given.

For security reasons I did not want to store my credentials in plaintext in the backup. So I wanted to give the cifs option "user" so that mount (and rear) will interactively asks my password. This was not possible with the current code. Additionally I found that when even giving the "cred" option to cifs, this was not detected by the current code. In other words it will still use the fallback "guest" option, even when cred option is set by the user in BACKUP_OPTIONS. Thanks

UPDATE: 
Commit2:
cryptsetup functionality was broken. Fixed and tested backup AND restore on a Fedora 17
1) luks UUID starting with a number was not correctly saved in the layout file. First number was missing
2) At restore time, the saved luks UUID was ignored when recreating the device which resulted in a failed boot on the restored machine (Dracut/initramfs which gets the command line options from grub2 was looking for the wrong luks UUID)