MINOR: stats: prevent favicon.ico requests for stats page

MINOR: stats: prevent favicon.ico requests for stats page

Haproxy stats page don't have a favicon.ico, but browsers always makes a request for it.
This lead to errors during stats page requests:

Aug 18 08:46:41 somehost.example.net haproxy[1521534]: X.X.X.X:61403 [18/Aug/2020:08:46:41.437] stats stats/ -1/-1/-1/-1/0 503 222 - - SC-- 2/2/0/0/0 0/0 "GET /favicon.ico HTTP/1.1"
Aug 18 08:46:42 somehost.example.net haproxy[1521534]: X.X.X.X:61403 [18/Aug/2020:08:46:42.650] stats stats/ -1/-1/-1/-1/0 503 222 - - SC-- 2/2/0/0/0 0/0 "GET /favicon.ico HTTP/1.1"

Patch provided disables favicon.ico requests for haproxy stats page.