Return error when user tries to upload attributes and attributes_str fields in same request.
Return error when user tries to upload attributes and attributes_str fields in same request.

MG-RAST/Shock,wgerlach/Shock,teharrison/Shock,MG-RAST/Shock,teharrison/Shock,MG-RAST/Shock,teharrison/Shock,wgerlach/Shock,MG-RAST/Shock,wgerlach/Shock,MG-RAST/Shock,teharrison/Shock,teharrison/Shock,teharrison/Shock,wgerlach/Shock,wgerlach/Shock