hgweb: don't make request optional

The "request" argument has been optional in this code since
it was introduced in 38170eeed18c in 2009. There are no consumers that
don't pass this argument. So don't make it an optional argument.

mercurial/hgweb/hgweb_mod.py

@@ -138,7 +138,7 b' class hgweb(object):'
         else:
             return repo.filtered('served')
 
-    def refresh(self, request=None):
+    def refresh(self, request):
         repostate = []
         # file of interrests mtime and size
         for meth, fname in foi:
@@ -163,8 +163,8 b' class hgweb(object):'
             self.repostate = repostate
             # mtime is needed for ETag
             self.mtime = st.st_mtime
-        if request:
-            self.repo.ui.environ = request.env
+
+        self.repo.ui.environ = request.env
 
     def run(self):
         """Start a server from CGI environment.