Add system/firewalld to manifest.

Bug: 22827985

default.xml

@@ -490,6 +490,7 @@
   <project path="system/connectivity/shill" name="platform/system/connectivity/shill" />
   <project path="system/core" name="platform/system/core" groups="pdk" />
   <project path="system/extras" name="platform/system/extras" groups="pdk" />
+  <project path="system/firewalld" name="platform/system/firewalld" />
   <project path="system/gatekeeper" name="platform/system/gatekeeper" groups="pdk" />
   <project path="system/keyguard" name="platform/system/keyguard" />
   <project path="system/keymaster" name="platform/system/keymaster" groups="pdk" />