JCLOUDS-622: Remove last vestiges of InputSupplier

Guava 16 deprecated InputSupplier and a future release will remove it.
@jdaggett I removed the interface changes and committed the other changes as fb60d76704745317186ad700e9b7ce5a569a614d.  I will resubmit this pull request and we can merge it after branching for 2.0.