use emplace where appropriate per clang-tidy

The clang-tidy warning 'modernize-use-emplace' correctly flags a
few places where emplace should be used over push.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I6ca79285a87d6927e718345dc8dce0387e6b1eda
diff --git a/redfish-core/lib/aggregation_service.hpp b/redfish-core/lib/aggregation_service.hpp
index 1cd2e68..83953fd 100644
--- a/redfish-core/lib/aggregation_service.hpp
+++ b/redfish-core/lib/aggregation_service.hpp
@@ -81,7 +81,7 @@
         member["@odata.id"] =
             crow::utility::urlFromPieces("redfish", "v1", "AggregationService",
                                          "AggregationSources", sat.first);
-        members.push_back(std::move(member));
+        members.emplace_back(std::move(member));
     }
     asyncResp->res.jsonValue["Members@odata.count"] = members.size();
     asyncResp->res.jsonValue["Members"] = std::move(members);