On port binding/unbinding, Kuryr catches exception raised from
pyroute2 and re-raise a new exception. As a result, the detailed
information contained in the original exception loses. This patch
adds a logging to record the original exception message and trace.
Related-Bug: #1776035
Change-Id: I4b13724a460d84a2b953f750b8b88c0f60cee97d