dashboard: fix tests

circle/dashboard/fixtures/test-vm-fixture.json

@@ -1462,7 +1462,6 @@
     "modified": "2014-01-24T00:58:19.654Z", 
     "system": "", 
     "priority": 20, 
-    "state": "READY", 
     "access_method": "ssh", 
     "raw_data": "", 
     "arch": "x86_64", 

circle/vm/models/instance.py

@@ -456,15 +456,6 @@ class Instance(AclBase, VirtualMachineDescModel, TimeStampedModel):
         else:
             return self.template.os_type
 
-    @property
-    def system(self):
-        """Get the instance's operating system.
-        """
-        if self.template is None:
-            return _("Unknown")
-        else:
-            return self.template.system
-
     def get_age(self):
         """Deprecated. Use uptime instead.