[CMake] CPack RPM : support for custom user spec file and post/pre install scripts

[Eric Noulard]

Hi CPack RPM user,

I did implement a new feature in CPack RPM generator which:

1) gives control of post/pre (un)install script of the RPM spec files
2) supports user provided spec file.

Any interested people should have a look at the tracker which contains
both a patch against CMake-2-6 branch or a drop-in replacement of
CPackRPM.cmake.

http://public.kitware.com/Bug/view.php?id=8988

( the other previous patch:
  http://public.kitware.com/Bug/view.php?id=8967
  may be applied too, they are non-overlapping)

-- 
Erk