src: Change adjacency status from uint32_t to enum

refs: #1946

Change-Id: Ic1abd2610061860d0ac183074395a1d3796e870a
diff --git a/src/adjacency-list.hpp b/src/adjacency-list.hpp
index 320dc40..76c9e5f 100644
--- a/src/adjacency-list.hpp
+++ b/src/adjacency-list.hpp
@@ -42,8 +42,8 @@
   int32_t
   insert(Adjacent& adjacent);
 
-  int32_t
-  updateAdjacentStatus(const ndn::Name& adjName, int32_t s);
+  bool
+  updateAdjacentStatus(const ndn::Name& adjName, Adjacent::Status s);
 
   int32_t
   updateAdjacentLinkCost(const ndn::Name& adjName, double lc);
@@ -60,11 +60,11 @@
   int32_t
   getTimedOutInterestCount(const ndn::Name& neighbor);
 
-  uint32_t
+  Adjacent::Status
   getStatusOfNeighbor(const ndn::Name& neighbor);
 
   void
-  setStatusOfNeighbor(const ndn::Name& neighbor, int32_t status);
+  setStatusOfNeighbor(const ndn::Name& neighbor, Adjacent::Status status);
 
   void
   setTimedOutInterestCount(const ndn::Name& neighbor, uint32_t count);