Upgrade WinBtrfs driver to v1.4

https://github.com/maharmstone/btrfs/releases/tag/v1.4

 v1.4 (2019-08-31):

• Added fragmentation percentage to property sheet
• Added support for Windows Server 2003 and Windows Vista
• Added pagefile support
• Improved support for file locking
• Added support for booting from Btrfs on Windows Server 2003 (see https://www.youtube.com/watch?v=-5E2CHmHEUs)
• Fixed issue where driver could open same inode twice
• Other miscellaneous bug fixes

PS: Since it now supports Windows Server 2003 some "compatibility changes" in our port could probably be removed and aligned to upstream.