In the CI smoke test, do not check for a ‘server’ header

It no longer seems to be present, and this particular header was not the
point of the test.

tests/smoke/test.py

@@ -3,7 +3,6 @@ import urllib3
 http = urllib3.PoolManager()
 r = http.request('GET', 'http://example.com/')
 print('status = {0}'.format(r.status))
-print("headers['server'] = {0}".format(r.headers['server']))
 print(r.data)
 if r.status != 200 or not r.data:
     raise SystemExit(1)