encoding: Remove SCOPE from Interests and all references to it in the related code

Change-Id: I2b19d0bb7ea5fdcea0da3996b946bb7797a9ea2d
Refs: #2345
diff --git a/src/encoding/tlv.hpp b/src/encoding/tlv.hpp
index da7b8ea..78564d8 100644
--- a/src/encoding/tlv.hpp
+++ b/src/encoding/tlv.hpp
@@ -65,7 +65,7 @@
   NameComponent = 8,
   Selectors     = 9,
   Nonce         = 10,
-  Scope         = 11, // deprecated
+  // <Unassigned> = 11,
   InterestLifetime          = 12,
   MinSuffixComponents       = 13,
   MaxSuffixComponents       = 14,
@@ -95,6 +95,7 @@
 enum SignatureTypeValue {
   DigestSha256 = 0,
   SignatureSha256WithRsa = 1,
+  // <Unassigned> = 2,
   SignatureSha256WithEcdsa = 3
 };