Modify mako script to generate code for empty interfaces

Empty interfaces are added for inventory objects to determine
the type of the object

Change-Id: I4b08e50a2ee45a3156012c0ef6b3ff53bd06c644
Signed-off-by: Marri Devender Rao <devenrao@in.ibm.com>
diff --git a/writefru.mako.hpp b/writefru.mako.hpp
index e27005f..fe84856 100755
--- a/writefru.mako.hpp
+++ b/writefru.mako.hpp
@@ -52,8 +52,9 @@
         intfName = names[0] + names[-1]
 %>\
     PropertyMap ${intfName}Props;
-        % for name, value in properties.iteritems():
-            % if fru and interface and name and value:
+        % if properties:
+            % for name, value in properties.iteritems():
+                % if fru and interface and name and value:
 <%
                 record, keyword = name.split(",")
 %>\
@@ -62,8 +63,9 @@
         ${intfName}Props["${value}"] =
             vpdStore.get<Record::${record}, record::Keyword::${keyword}>();
     }
-            % endif
-        % endfor
+                % endif
+            % endfor
+        % endif
     // Check and update extra properties
     if(extra::objects.end() != iter)
     {