BUG: fix rpmbuild bug, which expands variables in comments :-/

apparently rpmbuild can't handle paths with spaces and can't handle
variables in comments...

Alex

Modules/CPackRPM.cmake

@@ -189,7 +189,7 @@ ${CPACK_RPM_PACKAGE_DESCRIPTION}
 
 # This is a shortcutted spec file
 # generated by CMake RPM generator
-# we skip the %prepn %build and %install
+# we skip the _prepn _build and _install
 # steps because CPack does that for us
 #%prep