Relax rule for adding new patient in vtkDICOMDirectory.
Relax rule for adding new patient in vtkDICOMDirectory.

With DICOMDIR, a patient root is used so patients are always added
in order.  The OsiriX sql database uses a study root, so it is
necessary to allow patients to be handled out of order.  Thankfully,
it is a simple fix.

hendradarwin/vtk-dicom,dgobbi/vtk-dicom,hendradarwin/vtk-dicom,hendradarwin/vtk-dicom,dgobbi/vtk-dicom,dgobbi/vtk-dicom