from the MySQL 5.5 source tree.

Contrary to the comment, the spec file for these ULN RPMs
was missing in the previous changeset (blame ".bzrignore").

This change now brings said spec file, and it adds cmake
handling for the new files.

Still for internal tool tests only, not yet ready for publishing.


CMakeLists.txt:
  Add the subdirectory holding specific stuff
  for the RedHat-compatible RPMs for ULN.
cmake/install_layout.cmake:
  Explicitly mention my the ULN RPMs are handled.