lp: Packet::wireDecode checks TLV-TYPE of Block before decoding

refs #3256

Change-Id: Ia0fe8f88416eeecf969cc1a585e3625efe42e866
diff --git a/src/lp/packet.hpp b/src/lp/packet.hpp
index eed6b51..aa77a4f 100644
--- a/src/lp/packet.hpp
+++ b/src/lp/packet.hpp
@@ -60,6 +60,7 @@
 
   /**
    * \brief decode packet from wire format
+   * \throws Error unknown TLV-TYPE
    */
   void
   wireDecode(const Block& wire);