VShell: compat with old "protocol": print "Authentication failed" on auth fail
VShell: compat with old "protocol": print "Authentication failed" on auth fail

Server side VShell support script "vortexcmd" expects this string to be printed
on authentication failure.

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