util-lib: when copying files make sure to apply some chattrs early, some late

util-lib: when copying files make sure to apply some chattrs early, some late

Some chattrs only work sensible if you set them right after opening a
file for create (think: FS_NOCOW_FL). Others only work when they are
applied when the file is fully written (think: FS_IMMUTABLE_FL). Let's
take that into account when copying files and applying a chattr to them.