Replaced 'catch (std::out_of_range)' within objectstore/Helpers.cpp with...

Replaced 'catch (std::out_of_range)' within objectstore/Helpers.cpp with 'catch (std::out_of_range &)' in order to avoid the compilation error on newer compilers :catching polymorphic type ‘class std::out_of_range’ by value [-Werror=catch-value=]

objectstore/Helpers.cpp

@@ -299,7 +299,7 @@ std::string Helpers::selectBestRetrieveQueue(const std::set<std::string>& candid
         if (!g_retrieveQueueStatistics.at(v).tapeStatus.disabled)
           candidateVidsStats.emplace_back(g_retrieveQueueStatistics.at(v).stats);
       }
-    } catch (std::out_of_range) {
+    } catch (std::out_of_range &) {
       // We need to update the entry in the cache (miss or stale, we handle the same way).
       // We just update one vid at a time as doing several in parallel would be quite
       // hairy lock-wise (but give a slight performance boost).
@@ -560,4 +560,4 @@ std::list<cta::common::dataStructures::DriveState> Helpers::getAllDriveStates(Ba
 }
 
 
-}} // namespace cta::objectstore.
\ No newline at end of file
+}} // namespace cta::objectstore.