ART: Fix "unused parameters"

GCC 4.8 decides that parameters for functions implemented with
"= default" are unused. This currently only impacts x86, but remove
the parameter names anyways.

Change-Id: I01865faa81af68c4c0e0b1cb1fb19e88ef548769
diff --git a/runtime/base/variant_map.h b/runtime/base/variant_map.h
index c9718fc..8655a9e 100644
--- a/runtime/base/variant_map.h
+++ b/runtime/base/variant_map.h
@@ -120,8 +120,8 @@
 
    protected:
     // Avoid the object slicing problem; use Clone() instead.
-    VariantMapKeyRaw(const VariantMapKeyRaw& other) = default;
-    VariantMapKeyRaw(VariantMapKeyRaw&& other) = default;
+    VariantMapKeyRaw(const VariantMapKeyRaw&) = default;
+    VariantMapKeyRaw(VariantMapKeyRaw&&) = default;
 
    private:
     size_t key_counter_;  // Runtime type ID. Unique each time a new type is reified.
@@ -174,8 +174,8 @@
     deleter(reinterpret_cast<TValue*>(value));
   }
 
-  VariantMapKey(const VariantMapKey& other) = default;
-  VariantMapKey(VariantMapKey&& other) = default;
+  VariantMapKey(const VariantMapKey&) = default;
+  VariantMapKey(VariantMapKey&&) = default;
 
   template <typename Base, template <typename TV> class TKey> friend struct VariantMap;