Enable unused variable warnings and resolve

This commit enables the "unused variables" warning in clang.  Throughout
this, it did point out several issues that would've been functional
bugs, so I think it was worthwhile.  It also cleaned up several unused
variable from old constructs that no longer exist.

Tested:
Built with clang.  Code no longer emits warnings.

Downloaded bmcweb to system and pulled up the webui, observed webui
loads and logs in properly.

Change-Id: I51505f4222cc147d6f2b87b14d7e2ac4a74cafa8
Signed-off-by: Ed Tanous <ed@tanous.net>
diff --git a/include/redfish_v1.hpp b/include/redfish_v1.hpp
index cb7af8f..1e4bd65 100644
--- a/include/redfish_v1.hpp
+++ b/include/redfish_v1.hpp
@@ -10,7 +10,7 @@
 {
     BMCWEB_ROUTE(app, "/redfish/")
         .methods(boost::beast::http::verb::get)(
-            [](const crow::Request& req, crow::Response& res) {
+            [](const crow::Request&, crow::Response& res) {
                 res.jsonValue = {{"v1", "/redfish/v1/"}};
                 res.end();
             });