Remove versions from find_package(SoXt/SoWin), bug 928657.
Patch submitted upstream.

--- a/cmake/Modules/G4InterfaceOptions.cmake
+++ b/cmake/Modules/G4InterfaceOptions.cmake
@@ -153,12 +153,12 @@ if(GEANT4_USE_INVENTOR)
     geant4_save_package_variables(Inventor SoQt_DIR)
   else()
     if(UNIX)
-      find_package(SoXt 1.4.0 REQUIRED)
+      find_package(SoXt REQUIRED)
       check_sobind_version(SoXt 1.4.0)
       geant4_save_package_variables(Inventor SoXt_DIR)
       set(GEANT4_USE_INVENTOR_XT ON)
     elseif(WIN32)
-      find_package(SoWin 1.4.0 REQUIRED)
+      find_package(SoWin REQUIRED)
       check_sobind_version(SoWin 1.4.0)
       geant4_save_package_variables(Inventor SoWin_DIR)
       set(GEANT4_USE_INVENTOR_WIN ON)