field names

Add a test that proves the bug is fixed.  This doesn't add any
new server code.


mysql-test/r/federated.result:
  Verifying that one can use federated with keyword and bizarre 
  column names.
mysql-test/t/federated.test:
  Verifying that one can use federated with keyword and bizarre 
  column names.
  
  Eval interprets one level of backslash escaping, so some of this 
  may look strange.