PROTON-273: Removed the content Rspec test for Ruby.

Since the body of the message is accessed by the body property and not
by content, this test is no longer necessary.

Changed example apps to use body instead of content.

git-svn-id: https://svn.apache.org/repos/asf/qpid/proton/trunk@1528216 13f79535-47bb-0310-9956-ffa450edef68
PROTON-431: Fixed the assertions in the Ruby unit tests.

git-svn-id: https://svn.apache.org/repos/asf/qpid/proton/trunk@1528217 13f79535-47bb-0310-9956-ffa450edef68
PROTON-431: Fixed the Ruby spec tests.

They weren't updated with the changes to the Messenger.accept and
Messenger.settle API changes.

git-svn-id: https://svn.apache.org/repos/asf/qpid/proton/trunk@1528218 13f79535-47bb-0310-9956-ffa450edef68