The python-octaviaclient plugin was using "choices" for validating
port numbers and weights. The cliff "choices" parameter will output
an error that includes every valid "choice". For port numbers, this
is 65,000+ valid options.
This patch changes this to produce a more user friendly error
This patch also fixes the listener protocol-port type validation.
Octavia client was incoherent with Octavia's api-ref, hence it
supported only a subset of the possible combinations for specifying
VIP parameters in loadbalancer_create.
Validation functions were updated and moved from utils.py to
validate.py and load_balancer.py, accompanied by new unit tests.
Aesthetics: Refined loadabalancer's and l7Policy's creation synopses.