table: NameTree code style corrections

refs #3687

Change-Id: I25cfac1d8b11236c251c2ab717facb82b62dcb10
diff --git a/daemon/table/strategy-choice-entry.hpp b/daemon/table/strategy-choice-entry.hpp
index 9261039..e02a5ab 100644
--- a/daemon/table/strategy-choice-entry.hpp
+++ b/daemon/table/strategy-choice-entry.hpp
@@ -30,13 +30,14 @@
 
 namespace nfd {
 
-class NameTree;
-namespace name_tree {
-class Entry;
-} // namespace name_tree
 namespace fw {
 class Strategy;
 } // namespace fw
+namespace name_tree {
+class NameTree;
+class Entry;
+} // namespace name_tree
+using name_tree::NameTree;
 
 namespace strategy_choice {