Fix bug in ChecksumCalculatingInputStream

[varunnvs92]

Fix #941

Bug Description
When request has content stream, UrlConnectionHttpClient copies the content stream to the connection output stream using IoUtils.copy method. The copy methods writes to the outputStream until the endOfStream is reached ie., in.read method returns -1. As ChecksumCalculatingInputStream returns 0 for eos, the copy method goes into infinite loop.

Fix: Make read method return -1 when eos is reached.

Testing
Verified the tests in reported issue passed after the change.

• Its not possible to write tests in s3 module without adding url client module as dependency and forcing us to update all other tests to explicitly pick http client. Instead of that, I would prefer adding a module in test directory to add integ tests for S3 using UrlConnectionHttpClient. What do you think?
• Ideally we would need tests for all InputStream classes, but its not in the scope of the PR

[spfink]

What's the background for why this is breaking?

[zoewangg]

Can we add some tests?

[zoewangg]

Like the idea of putting the tests in http-client-tests module.

[varunnvs92]

Updated the PR with a new commit to fix dependency issues

[spfink]

LGTM still. Please rebase before pushing.