Changed catch(std::out_of_range) to catch(std::out_of_range &) in order to...

Changed catch(std::out_of_range) to catch(std::out_of_range &) in order to avoid the following type of compilation error:

../CTA/common/checksum/ChecksumBlob.hpp:145:18: error: catching polymorphic type ‘class std::out_of_range’ by value [-Werror=catch-value=]
     } catch(std::out_of_range) {
                  ^~~~~~~~~~~~
cc1plus: all warnings being treated as errors

common/checksum/ChecksumBlob.hpp

@@ -142,7 +142,7 @@ public:
   std::string at(ChecksumType type) const {
     try {
       return m_cs.at(type);
-    } catch(std::out_of_range) {
+    } catch(std::out_of_range &) {
       std::stringstream ss;
       ss << ChecksumTypeName.at(type) << " checksum not found. Checksum blob contents: "
          << *this;