SGComps: Demote WARNING to DEBUG.

SGInputLoader prints a warning if it's asked to load something
that's in a store other than the event store.
But this can happen normally if a handle is used to read objects
in the detector store, so demote this WARNING to DEBUG.

Control/SGComps/src/SGInputLoader.cxx

 ///////////////////////// -*- C++ -*- /////////////////////////////
 
 /*
-  Copyright (C) 2002-2017, 2019 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2017, 2019, 2020 CERN for the benefit of the ATLAS collaboration
 */
 
 // SGInputLoader.cxx 
@@ -114,8 +114,14 @@ SGInputLoader::execute()
       SG::VarHandleKey vhk(obj->clid(),obj->key(),Gaudi::DataHandle::Writer);
       if (StoreID::findStoreID(vhk.storeHandle().name()) == StoreID::EVENT_STORE) {
         toLoad.emplace(*obj);
-      } else {
-        ATH_MSG_WARNING("Will not auto-load proxy for non-EventStore object: "
+      }
+      else if (StoreID::findStoreID(vhk.storeHandle().name()) == StoreID::CONDITION_STORE) {
+        ATH_MSG_ERROR("Unresolved conditions dependency: "
+                        << *obj);
+        return StatusCode::FAILURE;
+      }
+      else {
+        ATH_MSG_DEBUG("Will not auto-load proxy for non-EventStore object: "
                         << *obj);
       }
     }