MEDIUM: check: align agentaddr and agentport behaviour

in the same manner of agentaddr, we now:
- permit to set agentport through `port` keyword, like it is the case
  for agentaddr through `addr`
- set the priority on `agent-port` keyword when used
- add a flag to be able to test when the value is set like for agentaddr

it makes the behaviour between `addr` and `port` more consistent.

Signed-off-by: William Dauchy <wdauchy@gmail.com>
4 files changed