CA-114777: Revert "Fix XenAPI.py on python2.7"

Unfortunately python2.4 doesn't work with this fix.

This reverts commit 7cd259574198123e9152db4a483bae54eed15c95.

Signed-off-by: John Else <john.else@citrix.com>
Merge pull request #1473 from johnelse/ca-114777

Revert "Fix XenAPI.py on python2.7"