VTK-3329 Fix formatting of current_timestamp when converted to string value.
VTK-3329 Fix formatting of current_timestamp when converted to string value.

Use of raw current_timestamp in vortex_resource goes without trouble, since the
date fields in that table are native database timestamps. However, date
properties in extra_prop_entry are stored as strings and must be formatted in a
way that Vortex can parse. Fix by using to_char() to format value from
current_timestamp.


vtkio/vtk,vtkio/vtk,vtkio/vtk,vtkio/vtk,vtkio/vtk,vtkio/vtk,vtkio/vtk,vtkio/vtk