Exclude from coverage hard-to-reach code

src/utils/Filesystem.hpp

@@ -14,9 +14,11 @@ createDirectoryIfNeeded(const std::string& filename)
     try {
       std::filesystem::create_directories(path);
     }
+    // LCOV_EXCL_START
     catch (std::filesystem::filesystem_error& e) {
       throw NormalError(e.what());
     }
+    // LCOV_EXCL_STOP
   }
 }