Do not use the deprecated best_match() method

This requires an upgrade of WebOb to 1.8.0.

Change-Id: Ifb0abb958ca30f19b4937384d9d732e2dc4e35a5

lower-constraints.txt

@@ -47,5 +47,5 @@ stevedore==1.20.0
 testtools==2.2.0
 traceback2==1.4.0
 unittest2==1.1.0
-WebOb==1.7.1
+WebOb==1.8.0
 wrapt==1.7.0

oslo_middleware/healthcheck/__init__.py

@@ -552,8 +552,10 @@ Reason
             status = self.HEAD_HEALTHY_TO_STATUS_CODES[healthy]
         else:
             status = self.HEALTHY_TO_STATUS_CODES[healthy]
-            accept_type = req.accept.best_match(self._accept_order)
-            if not accept_type:
+            try:
+                offers = req.accept.acceptable_offers(self._accept_order)
+                accept_type = offers[0][0]
+            except IndexError:
                 accept_type = self._default_accept
             functor = self._accept_to_functor[accept_type]
         body, content_type = functor(results, healthy)

requirements.txt

@@ -10,6 +10,6 @@ oslo.i18n>=3.15.3 # Apache-2.0
 oslo.utils>=3.33.0 # Apache-2.0
 six>=1.10.0 # MIT
 stevedore>=1.20.0 # Apache-2.0
-WebOb>=1.7.1 # MIT
+WebOb>=1.8.0 # MIT
 debtcollector>=1.2.0 # Apache-2.0
 statsd>=3.2.1 # MIT