add get_config_obj to a DataSource object.

This will allow for a DataSource to provide its own config
that will then be utilized as part of CloudConfig.
[to be used in OVF]

cloudinit/CloudConfig/__init__.py

@@ -49,6 +49,13 @@ class CloudConfig():
             cloudinit.log.debug(traceback.format_exc() + "\n")
             cfg = None
         if cfg is None: cfg = { }
+
+        try:
+            ds_cfg = self.cloud.datasource.get_config_obj()
+        except:
+            ds_cfg = { }
+
+        cfg = util.mergedict(cfg, ds_cfg)
         return(util.mergedict(cfg,self.cloud.cfg))
 
     def handle(self, name, args, freq=None):

cloudinit/DataSource.py

@@ -35,6 +35,13 @@ class DataSource:
     def get_userdata_raw(self):
         return(self.userdata_raw)
 
+
+    # the data sources' config_obj is a cloud-config formated
+    # object that came to it from ways other than cloud-config
+    # because cloud-config content would be handled elsewhere
+    def get_config_obj(self):
+        return({ })
+
     def get_public_ssh_keys(self):
         keys = []
         if not self.metadata.has_key('public-keys'): return([])