Fix build error: ‘temp’ may be used uninitialized in this function [-Werror=maybe-uninitialized]

Fixes #4753

test/unit/ImportExport/MDL/utMDLImporter_HL1_ImportSettings.cpp

@@ -205,7 +205,7 @@ private:
             const char *key_name) {
         aiNode *global_info = get_global_info(scene);
         EXPECT_NE(nullptr, global_info);
-        T temp;
+        T temp = 0;
         EXPECT_TRUE(global_info->mMetaData->Get(key_name, temp));
         EXPECT_EQ(expected_value, temp);
     }
@@ -216,7 +216,7 @@ private:
         aiNode *global_info = get_global_info(scene);
         EXPECT_NE(nullptr, global_info);
         for (auto it = p_kv.begin(); it != p_kv.end(); ++it) {
-            T temp;
+            T temp = 0;
             EXPECT_TRUE(global_info->mMetaData->Get(it->second, temp));
             EXPECT_EQ(it->first, temp);
         }