LIBCLOUD-378: S3 uploads fail on small iterators
Remove releases file, this will be moved into docs.
docs: Add "Committer Guide" section.
Fix s3 multipart test cases broken by LIBCLOUD-378

The breakage was caused by an overzealous check.
Also added test cases for checking small and big uploads via
S3 multipart upload API
docs: Add a note about removing credentials from debug output when sharing it
with others.
Merge branch 'trunk' of https://git-wip-us.apache.org/repos/asf/libcloud into trunk