suppress warning during compilation

src/storm/storage/expressions/UnaryNumericalFunctionExpression.cpp

@@ -44,6 +44,7 @@ namespace storm {
                     case OperatorType::Ceil: return static_cast<int_fast64_t>(std::ceil(result)); break;
                     default:
                         STORM_LOG_ASSERT(false, "All other operator types should have been handled before.");
+                        return 0;// Warning suppression.
                 }
             }
         }