MINOR: fix info message when global config is updated

[odoucet]

This pull request is refering to https://github.com/haproxytech/kubernetes-ingress/issues/652

CAREFUL I am absolutely not familiar with Go language (I'm a PHP guy). I tried to be very careful but please read my code carefully before accepting the commit.

EXPLANATIONS I removed the unused updated variable and fixed the error message. I just used the same syntax as line 149. I also used %+v to show field name (more explicit).