Upgrade WinBtrfs driver to v1.7.4 (or newer)

https://github.com/maharmstone/btrfs/releases/tag/v1.7.4

v1.7.4 (2020-08-23):

• Fixed issue when running compressed EXEs
• Changed build system to cmake
• Upgraded zstd to version 1.4.5
• Added support for FSCTL_GET_RETRIEVAL_POINTERS
• Miscellaneous bug fixes

https://github.com/maharmstone/btrfs/releases/tag/v1.7.3

v1.7.3 (2020-05-24):

• Fixed crash when sending file change notifications
• Improved symlink handling with LXSS
• Added support for undocumented flag SL_IGNORE_READONLY_ATTRIBUTE
• Fixed corruption caused by edge case, where address allocated and freed in same flush
• Improved handling of free space tree
• Improved handling of very full volumes
• Fixed spurious warnings raised by GCC 10 static analyser
• Replaced multiplications and divisions with bit shift operations where appropriate
• Fixed combobox stylings in shell extension