Fix test_bucket_location tests

[lincolnthomas]

The test_bucket_location() function in testcases/cloud_user/s3/bucket_tests.py fails if pointed to an AWS endpoint.

[lincolnthomas]

Made the test pass, for the default us-east-1 region only. Unfortunately, in AWS, if we create a bucket in another region, we can only delete it if we set up a new connection to that region and then delete it. New connections are outside the scope of these bucket tests.

Changes:

1. Changed bucket names to DNS-compliance (replacing underscores with periods).
2. In addition to bucket creation with no location specified, added bucket creation specifying us-east-1 (default location).
3. Skipped bucket creation in another region if testing against AWS.
4. Better logging of progress and results.

[lincolnthomas]

Further testing against AWS regions (us-east-1 and eu-west-1 Ireland) uncovered a few more gotchas. Fixed:

1. Setting bucket versioning and then immediately getting it can sometimes return the old value (failing the test). The versioning status seems to be eventually consistent. Added sleeps of 5 seconds between set and get. Even 2 seconds was not enough.
2. Erroneous error handling code discovered when EU region tested.
3. Clarified error messages and comments, and warnings when testing against AWS.