Fix some typos.

gns3server/controller/node.py

@@ -91,12 +91,12 @@ class Node:
 
         # Update node properties with additional elements
         for prop in kwargs:
-            if prop not in ignore_properties:
+            if prop and prop not in ignore_properties:
                 if hasattr(self, prop):
                     try:
                         setattr(self, prop, kwargs[prop])
                     except AttributeError as e:
-                        log.critical("Can't set attribute %s", prop)
+                        log.critical("Cannot set attribute '%s'".format(prop))
                         raise e
                 else:
                     if prop not in self.CONTROLLER_ONLY_PROPERTIES and kwargs[prop] is not None and kwargs[prop] != "":