Use -Werror in frameworks/native/cmds

* Remove or comment out unused variables/functions.

Bug: 66996870
Test: build with WITH_TIDY=1
Change-Id: I15a463eb9a20bc12787c104f671063ceeafaa1cc
diff --git a/cmds/bugreport/Android.bp b/cmds/bugreport/Android.bp
index 139e4b2..24044a6 100644
--- a/cmds/bugreport/Android.bp
+++ b/cmds/bugreport/Android.bp
@@ -1,6 +1,6 @@
 cc_binary {
     name: "bugreport",
     srcs: ["bugreport.cpp"],
-    cflags: ["-Wall"],
+    cflags: ["-Wall", "-Werror"],
     shared_libs: ["libcutils"],
 }