xfs: update for 3.20-rc1 This update contains: o RENAME_EXCHANGE support o Rework of the superblock logging infrastructure o Rework of the XFS_IOCTL_SETXATTR implementation - enables use inside user namespaces - fixes inconsistencies setting extent size hints o fixes for missing buffer type annotations used in log recovery o more consolidation of libxfs headers o preparation patches for block based PNFS support o miscellaneous bug fixes and cleanups