PROTON-215: Interop test: make finding AMQP fragments more robust.

Python: find the interop fragments by walking up the directory tree from __file__.
Java: Copy AMQP fragments as resources.

git-svn-id: https://svn.apache.org/repos/asf/qpid/proton/trunk@1446307 13f79535-47bb-0310-9956-ffa450edef68