Enable bugprone-unused-local-non-trivial-variable

And fix the two problems.

Change-Id: Ib91625d66e42fe8b14aaf1ef33761f9084564de9
Signed-off-by: Ed Tanous <ed@tanous.net>
diff --git a/.clang-tidy b/.clang-tidy
index 92c35a8..fb31ead 100644
--- a/.clang-tidy
+++ b/.clang-tidy
@@ -54,6 +54,7 @@
 bugprone-undelegated-constructor,
 bugprone-unhandled-exception-at-new,
 bugprone-unhandled-self-assignment,
+bugprone-unused-local-non-trivial-variable,
 bugprone-unused-raii,
 bugprone-unused-return-value,
 bugprone-use-after-move,