[Patch] Make samba4 return a correct Supported Encryption

[Matthieu Patou]

Hello,

Please Find attached a patch that allow S4 to return correctly the 
SupportedEncryption in the getDomainInfo RPC.

This patch make the assumption that by default if the 
msDS-SupportedEncryptionTypes is not populated then the workstation 
support all the encryption up to RC4 (same assumption as Windows 2008 
and upper do).

Matthieu.