Some modules only in groups if correct backend selected

These can only build with the OpenGL backend.

Change-Id: I7f95de24b0ad064a7ebe04b028cd9808857b35e4

Geovis/Core/module.cmake

+if(VTK_RENDERING_BACKEND STREQUAL "OpenGL")
+  set(_groups GROUPS Rendering)
+endif()
+
 vtk_module(vtkGeovisCore
-  GROUPS
-    Rendering
+  ${_groups}
   DEPENDS
     vtkIOXML
     vtkInteractionWidgets
     vtkInteractionStyle
     vtkInfovisLayout
     vtkViewsCore
-    vtkRenderingOpenGL2 # For vtkOpenGLHardwareSupport in vtkGeoTerrain
+    vtkRenderingOpenGL # For vtkOpenGLHardwareSupport in vtkGeoTerrain
     vtklibproj4
   TEST_DEPENDS
     vtkViewsGeovis

IO/Export/module.cmake

+if(VTK_RENDERING_BACKEND STREQUAL "OpenGL")
+  set(_groups GROUPS Rendering)
+endif()
 vtk_module(vtkIOExport
-  GROUPS
-    StandAlone
+  ${_groups}
   DEPENDS
     vtkCommonCore
     vtkRenderingAnnotation
@@ -9,7 +11,7 @@ vtk_module(vtkIOExport
     vtkRenderingFreeType
     vtkRenderingGL2PS
     vtkRenderingLabel
-    vtkRenderingOpenGL2
+    vtkRenderingOpenGL
     vtkImagingCore
   PRIVATE_DEPENDS
     vtkIOImage

Rendering/FreeTypeOpenGL/module.cmake

 vtk_module(vtkRenderingFreeTypeOpenGL
-  GROUPS
-    Rendering
   IMPLEMENTS
     vtkRenderingCore
+  BACKEND
+    OpenGL
   DEPENDS
     vtkRenderingFreeType
-    vtkRendering${VTK_RENDERING_BACKEND}
+    vtkRenderingOpenGL
   TEST_DEPENDS
     vtkTestingCore
     vtkTestingRendering

Rendering/LIC/module.cmake

+if(VTK_RENDERING_BACKEND STREQUAL "OpenGL")
+  set(_groups GROUPS Rendering)
+endif()
+
 vtk_module(vtkRenderingLIC
-  GROUPS
-    Rendering
+  ${_groups}
   DEPENDS
     vtkIOXML
     vtkIOLegacy
     vtkImagingSources
-    vtkRendering${VTK_RENDERING_BACKEND}
+    vtkRenderingOpenGL
   PRIVATE_DEPENDS
     vtksys
   TEST_DEPENDS

Views/Geovis/module.cmake

+if(VTK_RENDERING_BACKEND STREQUAL "OpenGL")
+  set(_groups GROUPS Rendering Views)
+endif()
 vtk_module(vtkViewsGeovis
-  GROUPS
-    Views
-    Rendering
+  ${_groups}
   DEPENDS
     vtkViewsInfovis
     vtkGeovisCore