Fix for Bug#1342913

Updated the REST client to send the correct "X-Container-Meta" header instead of using "X-Object-Meta".
Updated related unit tests, and rest simulator to use the right header values.
Updated the http abstraction unit tests to ensure that httpbin does not cache it's response headers.

Closes-Bug: #1342913
Change-Id: I020b21313da1ba77b37bbbe0cffb8c4f320f8ce6