We are creating a timestamp in the SigV4Auth class but this causes problems if you hold onto an endpoint for more than five minutes or so.  The timestamp expires and the signature is rejected.  We need to create a new timestamp each time add_auth is called.  But we also need a way to pass in a timestamp to use for the unit tests.  This fixes #149.
Just mock datetime.datetime.now() in the test generator rather than pushing into the auth class itself.
We are creating a timestamp in the SigV4Auth class but this causes problems if you hold onto an endpoint for more than five minutes or so.  The timestamp expires and the signature is rejected.  We need to create a new timestamp each time add_auth is called.  But we also need a way to pass in a timestamp to use for the unit tests.  This fixes #149.
Just mock datetime.datetime.now() in the test generator rather than pushing into the auth class itself.
Resolving merge conflicts.
Fix merge.
Merge branch 'fix-sigv4-timestamp' of git://github.com/garnaat/botocore into garnaat-fix-sigv4-timestamp