Revert "fuse: implement i_op->atomic_open()"

This reverts commit 1b7cf80b30c551a5d2459023cbfc06bac9a6d924.
Revert "fuse: invalidate inode mapping if mtime changes"

This reverts commit b9a33da78656ae0e3f27b18d1fcc410f2503fe4a.
Revert "fuse: update attributes on aio_read"

This reverts commit f12ed383e92f094a95ae2bd5772357a6fb6926ea.