Improve the update of roottest clone

CMakeLists.txt

@@ -123,21 +123,17 @@ endif()
 if(testing)
   include(RootCTest)
   if(roottest)
+    find_package(Git REQUIRED)
     if(IS_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/roottest)
       execute_process(COMMAND ${GIT_EXECUTABLE} pull WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/roottest)
       add_subdirectory(roottest)
     elseif(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/../roottest)
       add_subdirectory(../roottest roottest)
     else()
-      find_package(Git)
-      if(NOT GIT_EXECUTABLE)
-        message(FATAL_ERROR "-- Could not find git needed to clone roottest directory!")
-      else()
-        message("-- Could not find roottest directory! Cloning from the repository...")
-        execute_process(COMMAND ${GIT_EXECUTABLE} clone http://root.cern.ch/git/roottest.git
-                        WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR})
-        add_subdirectory(roottest)
-      endif()
+      message("-- Could not find roottest directory! Cloning from the repository...")
+      execute_process(COMMAND ${GIT_EXECUTABLE} clone http://root.cern.ch/git/roottest.git
+                      WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR})
+      add_subdirectory(roottest)
     endif()
   endif()
 endif()