Fix all our unused parameter warnings so we let GCC report them.

There were a couple of genuine bugs here (fixed), plus there's a missing
feature in trace.cc that I've just added a TODO for.

Also note that I haven't touched the compilers; this warning is still
explicitly disabled for that code. I'll do that when there's less going
on in those directories.

Change-Id: Ic3570bf82411a07c7530bfaf1995ac995b9fc00f
diff --git a/src/dex_file.cc b/src/dex_file.cc
index 850415e..d3e1c68 100644
--- a/src/dex_file.cc
+++ b/src/dex_file.cc
@@ -143,7 +143,7 @@
     return NULL;
   }
 
-  if (!DexFileVerifier::Verify(dex_file, dex_file->Begin(), dex_file->Size())) {
+  if (verify && !DexFileVerifier::Verify(dex_file, dex_file->Begin(), dex_file->Size())) {
     LOG(ERROR) << "Failed to verify dex file '" << filename << "'";
     return NULL;
   }