[CMake] Remove unreachable configuration code branch

ROOT requires C++17 as the minimum C++ standard anyway.

Author: guitargeek

cmake/modules/SearchInstalledSoftware.cmake

@@ -1030,16 +1030,6 @@ if(arrow)
       message(STATUS "For the time being switching OFF 'arrow' option")
       set(arrow OFF CACHE BOOL "Disabled because Apache Arrow API not found (${arrow_description})" FORCE)
     endif()
-  else()
-    if(${ARROW_VERSION} VERSION_GREATER_EQUAL 10.0.0 AND CMAKE_CXX_STANDARD LESS 17)
-      if(fail-on-missing)
-        message(SEND_ERROR "The Apache Arrow version found on the system (${ARROW_VERSION}) requires at least CMAKE_CXX_STANDARD=17")
-      else()
-        message(STATUS "The Apache Arrow version found on the system (${ARROW_VERSION}) requires at least CMAKE_CXX_STANDARD=17")
-        message(STATUS "For the time being switching OFF 'arrow' option")
-        set(arrow OFF CACHE BOOL "Disabled because Apache Arrow Version ${ARROW_VERSION} requires CMAKE_CXX_STANDARD=17)" FORCE)
-      endif()
-    endif()
   endif()
 
 endif()