In the three commands that take a --transport-url option,
or reads it from config, this will validate the tranport URL is
valid by calling the parsing code in oslo.messaging and fail
if the URL does not parse correctly.
Change-Id: If60cdf697cab2f035cd22830303f5ecaba0f3969
Closes-Bug: #1770341
Matt Riedemann
bc6ca87a6a