re-add try statement

...that was lost in the merge
Signed-off-by: Klaus Aehlig <aehlig@google.com>
Reviewed-by: Hrvoje Ribicic <riba@google.com>

lib/config.py

@@ -2515,7 +2515,8 @@ class ConfigWriter(object):
     # Read the configuration data. If offline, read the file directly.
     # If online, call WConfd.
     if self._offline:
-      raw_data = utils.ReadFile(self._cfg_file)
+      try:
+        raw_data = utils.ReadFile(self._cfg_file)
         data_dict = serializer.Load(raw_data)
         # Make sure the configuration has the right version
         _ValidateConfig(data_dict)