ipa-sam: report supported enctypes based on Kerberos realm configuration
We store Kerberos realm configuration in cn=REALM,cn=kerberos,$SUFFIX.
Along other configuration options, this container has list of default
supported encryption types, in krbDefaultEncSaltTypes.
Fetch krbDefaultEncSaltTypes value on ipa-sam initialization and convert
discovered list to the mask of supported encryption types according to
security.idl from Samba:
typedef [public,bitmap32bit] bitmap {
KERB_ENCTYPE_DES_CBC_CRC = 0x00000001,
KERB_ENCTYPE_DES_CBC_MD5 = 0x00000002,
KERB_ENCTYPE_RC4_HMAC_MD5 = 0x00000004,
KERB_ENCTYPE_AES128_CTS_HMAC_SHA1_96 = 0x00000008,
KERB_ENCTYPE_AES256_CTS_HMAC_SHA1_96 = 0x00000010
} kerb_EncTypes;
Part of https://fedorahosted.org/freeipa/ticket/3898