hgweb: ignore filtered revision in revnav

This changeset checks that a revision is known before adding it to the
navigation.

This will prevent traceback on filtered repository. This changeset result in an
incorrect behaviors, Navigation link may be dropped without any replacement.
However this bad navigation generation is much better than a crash

mercurial/hgweb/webutil.py

@@ -88,6 +88,8 b' class revnav(object):'
         navbefore = [("(0)", self.hex(0))]
         navafter = []
         for rev in targets:
+            if rev not in self._revlog:
+                continue
             if pos < rev < limit:
                 navafter.append(("+%d" % f, self.hex(rev)))
             if 0 < rev < pos:

tests/test-obsolete.t

@@ -679,16 +679,15 b' check hgweb does not explode'
   $ hg serve -n test -p $HGPORT -d --pid-file=hg.pid -A access.log -E errors.log
   $ cat hg.pid >> $DAEMON_PIDS
 
-#check changelog view
-#
-#  $ "$TESTDIR/get-with-headers.py" --headeronly localhost:$HGPORT 'shortlog/'
-#  200 Script output follows
+check changelog view
+
+  $ "$TESTDIR/get-with-headers.py" --headeronly localhost:$HGPORT 'shortlog/'
+  200 Script output follows
 
 #check graph view
 #
 #  $ "$TESTDIR/get-with-headers.py" --headeronly localhost:$HGPORT 'graph'
 #  200 Script output follows
-
 check filelog view
 
   $ "$TESTDIR/get-with-headers.py" --headeronly localhost:$HGPORT 'log/'`hg id --debug --id`/'babar'