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/CMakeLists.txt b/CMakeLists.txt
index 847a43e..9d5aa63 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -205,7 +205,7 @@
             -Wnull-dereference \
             -Wdouble-promotion \
             -Wformat=2 \
-            -Wno-unused-parameter \
+            -Wunused-parameter \
         "
         )
     endif (CMAKE_CXX_COMPILER_VERSION VERSION_GREATER 8.0)
@@ -228,7 +228,7 @@
             -Wno-weak-vtables \
             -Wno-documentation \
             -Wno-padded \
-            -Wno-unused-parameter \
+            -Wunused-parameter \
             -Wcovered-switch-default \
             -Wcomma \
             -Wextra-semi \