* Don't call single_row() with an undeclared and unused $taxonomy argument.
* Don't define optional parameters before required parameters in the _rows() method. Make them required.
* Move empty( $terms ) check above other operations. This function was improperly returning an else case until [24123].
props rlerdorf.
see #24210.
git-svn-id: https://develop.svn.wordpress.org/trunk@24127 602fd350-edb4-49c9-b593-d223f7449a82
