management: Correct type for setFaceId/getFaceId (int -> uint64_t)

Change-Id: Ib6afcf59802b93c0705fd24d61ec145cb0db0eb7
diff --git a/src/management/nrd-prefix-reg-options.hpp b/src/management/nrd-prefix-reg-options.hpp
index 8bb3f7e..12136e8 100644
--- a/src/management/nrd-prefix-reg-options.hpp
+++ b/src/management/nrd-prefix-reg-options.hpp
@@ -69,14 +69,14 @@
 
   //
   
-  int
+  uint64_t
   getFaceId() const
   {
     return m_faceId;
   }
 
   PrefixRegOptions&
-  setFaceId(int faceId)
+  setFaceId(uint64_t faceId)
   {
     m_faceId = faceId;
     m_wire.reset();