fix web2py/web2py#693 (uploadfolder is not defined by mongo Adapter)
fix web2py/web2py#693 (uploadfolder is not defined by mongo Adapter)

web2py/pydal,manuelep/pydal,willimoa/pydal,michele-comitini/pydal,kmcheung12/pydal,niphlod/pydal,stephenrauch/pydal