#24 base/POST not honor config fallback

[Bryan Gartner]

for files like POST-YUM (and the correspoding POST-distro-ver-arch), there is no fallback to POST-distro-ver), so have to have lots more explicit links than would be necessary if it honored it

[leem]

Checking the code we indeed do not honor the tuple fallback in base/PRE MID POST. Will correct.