Fixed DescribeUser in the ec2 admin client to return None instead of an empty UserInfo object.

nova/adminclient.py

@@ -324,14 +324,11 @@ class NovaAdminClient(object):
 
     def get_user(self, name):
         """Grab a single user by name."""
-        try:
-            return self.apiconn.get_object('DescribeUser',
-                                           {'Name': name},
-                                           UserInfo)
-        except boto.exception.BotoServerError, e:
-            if e.status == 400 and e.error_code == 'NotFound':
-                return None
-            raise
+        user = self.apiconn.get_object('DescribeUser',
+                                       {'Name': name},
+                                       UserInfo)
+        if user.username != None:
+            return user
 
     def has_user(self, username):
         """Determine if user exists."""