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/http/http_client.hpp b/http/http_client.hpp
index c455c7b..f4c3346 100644
--- a/http/http_client.hpp
+++ b/http/http_client.hpp
@@ -257,11 +257,11 @@
             BMCWEB_LOG_DEBUG << "Attempt retry after " << retryIntervalSecs
                              << " seconds. RetryCount = " << retryCount;
             timer.expires_after(std::chrono::seconds(retryIntervalSecs));
-            timer.async_wait([self = shared_from_this()](
-                                 const boost::system::error_code& ec) {
-                self->runningTimer = false;
-                self->connStateCheck();
-            });
+            timer.async_wait(
+                [self = shared_from_this()](const boost::system::error_code&) {
+                    self->runningTimer = false;
+                    self->connStateCheck();
+                });
             return;
         }
         else