contrib: smb2: update to 4.0.0

Changelog since 3.0.0:

• Add support for SMB3 encryption
• Add support for Anonymous NTLMSSP logins
• Add support for readlink.
• Add API to notify application of changes to which filehandles are used by libsmb2.
• Add suppport for Big Endian DCERPC and allow it to be controlled from the URL.
• Add support for 3.1.1 signing
• Add support for PS2(EE) and PS3
• Fixes to UCS2 when compose characters are used.
• Various MacOS fixes
• Fix a few NULL dereferences

All theses fixes were already included in the contrib version.