Bugfix: make old_dof_indices ordering consistent

We moved the SCALAR dofs to their variable number position in
dof_indices, but didn't make the same update to old_dof_indices
Fix cut-and-paste atavism

Apparently vim's d and p commands are not artificially intelligent.
I should file a feature request.
Merge pull request #340 from libMesh/old_SCALAR_indices

Bugfix: make old_dof_indices ordering consistent