Move use of option values after call to ROOT_APPLY_OPTIONS()

Option values *must not be used* before calling the function
ROOT_APPLY_OPTIONS(). This function is responsible for setting
all values using the defaults and what was passed on the command
line, so values before the call are not what the user asked for.

cmake/modules/RootBuildOptions.cmake

@@ -328,14 +328,14 @@ endif()
 #---webgui by default always build together with root7-----------------------------------------
 set(webgui_defvalue ${root7_defvalue})
 
+#---Define at moment the options with the selected default values-----------------------------
+ROOT_APPLY_OPTIONS()
+
 #---roottest option implies testing
 if(roottest OR rootbench)
   set(testing ON CACHE BOOL "" FORCE)
 endif()
 
-#---Define at moment the options with the selected default values-----------------------------
-ROOT_APPLY_OPTIONS()
-
 if(root7)
   if(NOT CMAKE_CXX_STANDARD)
     set(CMAKE_CXX_STANDARD 14 CACHE STRING "C++14 standard used with root7")