Modify mako script to generate code for empty interfaces

Allow generating code for empty interfaces in the FRU map.
Empty interfaces are used to determine the type of the
inventory object.

Change-Id: I945998627b88bc68374b631d1b14328cd611cb39
Signed-off-by: Marri Devender Rao <devenrao@in.ibm.com>
diff --git a/scripts/writefru.mako.cpp b/scripts/writefru.mako.cpp
index 82941a4..0a0a14f 100644
--- a/scripts/writefru.mako.cpp
+++ b/scripts/writefru.mako.cpp
@@ -12,10 +12,11 @@
          {"${object}",{
          % for interface,properties in interfaces.items():
              {"${interface}",{
-            % for dbus_property,property_value in properties.items():
-                 {"${dbus_property}",{
-                     "${property_value.get("IPMIFruSection", "")}",
-                     "${property_value.get("IPMIFruProperty", "")}", \
+            % if properties:
+                % for dbus_property,property_value in properties.items():
+                    {"${dbus_property}",{
+                        "${property_value.get("IPMIFruSection", "")}",
+                        "${property_value.get("IPMIFruProperty", "")}", \
 <%
     delimiter = property_value.get("IPMIFruValueDelimiter")
     if not delimiter:
@@ -25,7 +26,8 @@
 %>
                      "${delimiter}"
                  }},
-            % endfor
+                % endfor
+            %endif
              }},
          % endfor
         }},