builder: tests: Fix virt-builder --list output.

This fixes commit a27963b67ba1140c29c145a1ce14dbfc05f8d7da.
builder: tests: Add test-virt-builder-planner.sh to EXTRA_DIST.

This fixes commit a27963b67ba1140c29c145a1ce14dbfc05f8d7da.
builder: Add a link to blog posting about the planner.

http://rwmj.wordpress.com/2013/12/14/writing-a-planner-to-solve-a-tricky-programming-optimization-problem/
should help people to understand how this code works.
Version 1.25.15.