Revert "Revert "Fix incorrect defaultValue in generated server.hpp""

This reverts commit 8192be92b9bf50450eb309a8798b3895bfdae471.

The commit "Fix incorrect defaultValue in generated server.hpp" revealed
an issue in phosphor-dbus-interfaces that causes the build error, and it
was reverted temporarily.

The issue is fixed in phosphor-dbus-interface, so we could add it back.

Change-Id: I1700ff1ede5f0eedc11fc324f649ea4f2e76edf5
Signed-off-by: Lei YU <mine260309@gmail.com>
diff --git a/tools/sdbusplus/property.py b/tools/sdbusplus/property.py
index fb774b6..83d9f3a 100644
--- a/tools/sdbusplus/property.py
+++ b/tools/sdbusplus/property.py
@@ -11,6 +11,12 @@
         self.flags = kwargs.pop('flags', [])
         self.errors = kwargs.pop('errors', [])
 
+        # Convert True/False to 'true'/'false'
+        # because it will be rendered as C++ code
+        if (self.defaultValue is not None and
+                isinstance(self.defaultValue, bool)):
+            self.defaultValue = 'true' if self.defaultValue else 'false'
+
         super(Property, self).__init__(**kwargs)
 
     def is_enum(self):
diff --git a/tools/sdbusplus/templates/interface.mako.server.hpp b/tools/sdbusplus/templates/interface.mako.server.hpp
index b263c7a..0774fe5 100644
--- a/tools/sdbusplus/templates/interface.mako.server.hpp
+++ b/tools/sdbusplus/templates/interface.mako.server.hpp
@@ -139,7 +139,7 @@
         sdbusplus::SdBusInterface *_intf;
 
     % for p in interface.properties:
-        % if p.defaultValue:
+        % if p.defaultValue is not None:
         ${p.cppTypeParam(interface.name)} _${p.camelCase} = \
             % if p.is_enum():
 ${p.cppTypeParam(interface.name)}::\