Fix logging exceptions generating bad format strings. Oops.

src/dds/util/parallel.cpp

@@ -8,6 +8,6 @@ void dds::log_exception(std::exception_ptr eptr) noexcept {
     try {
         std::rethrow_exception(eptr);
     } catch (const std::exception& e) {
-        dds_log(error, e.what());
+        dds_log(error, "{}", e.what());
     }
 }