Modify mako script to generate code for empty interfaces

Allow generating empty interfaces in the FRU map, which are
used to determine the type of the inventory object.

Change-Id: I6dc97514b0bdf7ef9d3a63ee6790a7933b3e7cd9
Signed-off-by: Marri Devender Rao <devenrao@in.ibm.com>
diff --git a/scripts/readfru.mako.cpp b/scripts/readfru.mako.cpp
index 40e4812..061b4e0 100644
--- a/scripts/readfru.mako.cpp
+++ b/scripts/readfru.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
         }},