make several modules depend on the "open" module

make several modules depend on the "open" module

This provides slightly increased consistency when opening-for-write
the name of a non-directory spelled with a trailing slash.
* modules/chdir-safer: Likewise.
* modules/chown: Likewise.
* modules/clean-temp: Likewise.
* modules/copy-file: Likewise.
* modules/fchdir: Likewise.
* modules/fcntl-safer: Likewise.
* modules/pipe: Likewise.
* modules/utime: Likewise.
Prompted by Eric Blake and Bruno Haible.