Comment # 17 on bug 1029961 from Stanislav Brabec

Ludwig Nussel, comment 16:

3) - do not package compat symlinks. Run something post install of
     each package that installs such links if /bin is a directory and
     the package /bin/$something in it's provides tags.
   - Make the initrd move away /bin and install the /bin -> /usr/bin
     symlink (same for sbin and lib).

If would work only if /bin will not be a symlink.

But if /bin will not be a symlink, we do not need any hacks. Such upgrade works
out of the box.

Replacement of file by symlink is supported by RPM.

Replacement of directory by symlink is not supported by RPM.