Use pass-by-value in constructor

Pass by rvalue reference results in
build errors when using CLN

src/storm-pomdp/storage/BeliefManager.cpp

@@ -14,7 +14,7 @@ namespace storm {
         }
 
         template<typename PomdpType, typename BeliefValueType, typename StateType>
-        BeliefManager<PomdpType, BeliefValueType, StateType>::FreudenthalDiff::FreudenthalDiff(StateType const &dimension, BeliefValueType &&diff) : dimension(dimension),
+        BeliefManager<PomdpType, BeliefValueType, StateType>::FreudenthalDiff::FreudenthalDiff(StateType const &dimension, BeliefValueType diff) : dimension(dimension),
                                                                                                                                                      diff(std::move(diff)) {
             // Intentionally left empty
         }

src/storm-pomdp/storage/BeliefManager.h

@@ -76,7 +76,7 @@ namespace storm {
             };
 
             struct FreudenthalDiff {
-                FreudenthalDiff(StateType const &dimension, BeliefValueType &&diff);
+                FreudenthalDiff(StateType const &dimension, BeliefValueType diff);
 
                 StateType dimension; // i
                 BeliefValueType diff; // d[i]