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/redfish-core/include/privileges.hpp b/redfish-core/include/privileges.hpp
index d9bf1fc..2d44545 100644
--- a/redfish-core/include/privileges.hpp
+++ b/redfish-core/include/privileges.hpp
@@ -309,7 +309,7 @@
  */
 inline bool isMethodAllowedForUser(const boost::beast::http::verb method,
                                    const OperationMap& operationMap,
-                                   const std::string& user)
+                                   const std::string&)
 {
     // TODO: load user privileges from configuration as soon as its available
     // now we are granting all privileges to everyone.