KDE fails to start with "Could not start D-Bus. Can you call qdbus?"

I had been running Fedora 19 for quite a while with KDE as my desktop happily. Then one day after a yum update I could no longer start KDE. An error message appeared each time I tried to start KDE from login.

Could not start D-Bus. Can you call qdbus?

After some debugging it turns out that kde4-config --qt-binaries returns /usr/bin/bin as the location of the Qt binaries, which is a bogus directory. 

# kde4-config --qt-binaries

/usr/bin/bin

I have temporarily worked around the problem by creating a soft link from /usr/bin/bin to /usr/bin while I search for a proper solution.