Start using sdbusplus::message::filename()

Lots of code gets checked in that does this path checking incorrectly.
So much so, that we have it documented in COMMON_ERRORS.md, yet, we
persist.  This patchset starts using the new object_path::filename()
method that was added recently to sdbusplus.  Overall, it deletes code,
and makes for a much better developer experience.

Tested:
Pulled down several endpoints and verified that filename() method works
properly, and the collections are returned as expected.

curl -vvvv --insecure --user root:0penBmc https://192.168.7.2/redfish/v1/AccountService/Accounts

Signed-off-by: Ed Tanous <edtanous@google.com>
Change-Id: Ief1e0584394fb139678d3453265f7011bc931f3c
diff --git a/redfish-core/include/utils/collection.hpp b/redfish-core/include/utils/collection.hpp
index bcf5c16..f1b7f21 100644
--- a/redfish-core/include/utils/collection.hpp
+++ b/redfish-core/include/utils/collection.hpp
@@ -44,13 +44,16 @@
 
             for (const auto& object : objects)
             {
-                auto pos = object.rfind('/');
-                if ((pos != std::string::npos) && (pos < (object.size() - 1)))
+                sdbusplus::message::object_path path(object);
+                std::string leaf = path.filename();
+                if (leaf.empty())
                 {
-                    members.push_back(
-                        {{"@odata.id",
-                          collectionPath + "/" + object.substr(pos + 1)}});
+                    continue;
                 }
+                std::string newPath = collectionPath;
+                newPath += '/';
+                newPath += leaf;
+                members.push_back({{"@odata.id", std::move(newPath)}});
             }
             aResp->res.jsonValue["Members@odata.count"] = members.size();
         },