fixes bug 964491 by replacing socorro.lib.uuid with stdlib

`socorro.lib.uuid` was a backport of a python 2.5 standard library
in the initial socorro check in (when socorro ran on python 2.4). Now
that we require 2.6 at a minimum, we can safely replace it and all
internal references to it with the standard library `uuid`
Merge pull request #1834 from lonnen/964491-uuid

fixes bug 964491 by replacing socorro.lib.uuid with stdlib