https://fedorahosted.org/freeipa/ticket/5183

Reviewed-By: Tomas Babej <tbabej@redhat.com>

For Windows Server 2012R2 and others which force SMB2 protocol use
we have to specify right DCE RPC binding options.

For using SMB1 protocol we have to omit specifying SMB2 protocol and
anything else or otherwise SMB1 would be considered a pipe to connect
to. This is by design of a binding string format.

https://fedorahosted.org/freeipa/ticket/5183

Reviewed-By: Tomas Babej <tbabej@redhat.com>

Use Python-3 compatible syntax, without breaking compatibility with py 2.7

- Octals literals start with 0o to prevent confusion
- The "L" at the end of large int literals is not required as they use
  long on Python 2 automatically.
- Using 'int' instead of 'long' for small numbers is OK in all cases except
  strict type checking checking, e.g. type(0).

https://fedorahosted.org/freeipa/ticket/4985

Reviewed-By: Jan Cholasta <jcholast@redhat.com>

This patch removes the dependency on M2Crypto in favor for cryptography.
Cryptography is more strict about the key size and doesn't support
non-standard key sizes:

>>> from M2Crypto import RC4
>>> from ipaserver.dcerpc import arcfour_encrypt
>>> RC4.RC4(b'key').update(b'data')
'o\r@\x8c'
>>> arcfour_encrypt(b'key', b'data')
Traceback (most recent call last):
...
ValueError: Invalid key size (24) for RC4.

Standard key sizes 40, 56, 64, 80, 128, 192 and 256 are supported:

>>> arcfour_encrypt(b'key12', b'data')
'\xcd\xf80d'
>>> RC4.RC4(b'key12').update(b'data')
'\xcd\xf80d'

http://cryptography.readthedocs.org/en/latest/hazmat/primitives/symmetric-encryption/#cryptography.hazmat.primitives.ciphers.algorithms.ARC4
https://fedorahosted.org/freeipa/ticket/5148

Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Jan Cholasta <jcholast@redhat.com>

Reviewed-By: Tomas Babej <tbabej@redhat.com>

https://fedorahosted.org/freeipa/ticket/5029

Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>

Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>

It's possible for AD to contact a wrong IPA server in case the DNS
SRV records on the AD sides are not properly configured.

Mention this case in the error message as well.

https://fedorahosted.org/freeipa/ticket/5013

Reviewed-By: Petr Vobornik <pvoborni@redhat.com>

Instead of separate checking of DNS required packages, we need just
check if IPA DNS package is installed.

https://fedorahosted.org/freeipa/ticket/4058

Reviewed-By: Martin Babinsky <mbabinsk@redhat.com>
Reviewed-By: Petr Spacek <pspacek@redhat.com>
Reviewed-By: Tomas Babej <tbabej@redhat.com>

python3 does not allow to mix spaces and tabs

Reviewed-By: Christian Heimes <cheimes@redhat.com>