[common] Remove unused member in KeyEncoderTraits

Change-Id: Ia36fd64f9c9219f7ab16dd264a49bccab31aaca6
Reviewed-on: http://gerrit.cloudera.org:8080/14506
Tested-by: Kudu Jenkins
Reviewed-by: Adar Dembo <adar@cloudera.com>
diff --git a/src/kudu/common/key_encoder.h b/src/kudu/common/key_encoder.h
index 92b9bac..5b2cd76 100644
--- a/src/kudu/common/key_encoder.h
+++ b/src/kudu/common/key_encoder.h
@@ -61,8 +61,6 @@
                           >::value
                         >::type
                        > {
-  static const DataType key_type = Type;
-
  private:
   typedef typename DataTypeTraits<Type>::cpp_type cpp_type;
   typedef typename MathLimits<cpp_type>::UnsignedType unsigned_cpp_type;
@@ -122,9 +120,6 @@
 
 template<typename Buffer>
 struct KeyEncoderTraits<BINARY, Buffer> {
-
-  static const DataType key_type = BINARY;
-
   static void Encode(const void* key, Buffer* dst) {
     Encode(*reinterpret_cast<const Slice*>(key), dst);
   }