make enabling/disabling of dd4hep tests more understandable

Det/DetCond/CMakeLists.txt

@@ -84,17 +84,8 @@ set_property(
         ENVIRONMENT GIT_TEST_REPOSITORY=${CMAKE_CURRENT_BINARY_DIR}/test_repo
 )
 
-# disable DD4HEP specific tests
-if(NOT USE_DD4HEP)
-  set_property(
-      TEST
-          DetCond.condition_accessor.dd4hep_check_db_access
-          DetCond.condition_accessor.dd4hep_check_db_access_bare
-          DetCond.condition_accessor.dd4hep_conditions
-      APPEND PROPERTY
-      DISABLED TRUE
-  )
-else()
+if(USE_DD4HEP)
+    # disable DetDesc specific tests
     set_property(
         TEST
             DetCond.condition_accessor.begin_event_and_reserve
@@ -104,4 +95,14 @@ else()
         APPEND PROPERTY
         DISABLED TRUE
     )
+else()
+    # disable DD4HEP specific tests
+    set_property(
+        TEST
+            DetCond.condition_accessor.dd4hep_check_db_access
+            DetCond.condition_accessor.dd4hep_check_db_access_bare
+            DetCond.condition_accessor.dd4hep_conditions
+        APPEND PROPERTY
+        DISABLED TRUE
+    )
 endif()