[Paraview] git update instructions

[David Doria]

I have not updated ParaView in a while. I followed the instructions here:
http://www.vtk.org/Wiki/ParaView/Git/Download

and did a 'git pull origin master' followed by a 'git submodule
update'. However, when I then configure, I get:

 CMake Error at CMake/ParaViewCommon.cmake:520 (ADD_SUBDIRECTORY):
   The source directory

     /home/doriad/src/ParaView/Utilities/protobuf

   does not contain a CMakeLists.txt file.

I'm assuming this is because when I first cloned ParaView the protobuf
submodule did not exist? Should an extra command be added to that wiki
page so that new submodules are found?

Thanks,

David