Encode point clear to match spec

VersionedMap.cpp

@@ -839,7 +839,7 @@ VersionedMap::Iterator::operator*() const {
     return {entry.getKey(),    entry.getVal(), entry.keyLen, entry.valLen, Set,
             entry.pointVersion};
   } else {
-    return {entry.getKey(), nullptr,           entry.keyLen, -1,
+    return {entry.getKey(), nullptr,           entry.keyLen, 0,
             Clear,          entry.pointVersion};
   }
 }