hgweb: ignore filtered revision in revnav

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

--- a/mercurial/hgweb/webutil.py	Thu Jan 10 19:29:48 2013 +0100
+++ b/mercurial/hgweb/webutil.py	Wed Jan 16 14:19:28 2013 +0100
@@ -88,6 +88,8 @@
         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:

--- a/tests/test-obsolete.t	Thu Jan 10 19:29:48 2013 +0100
+++ b/tests/test-obsolete.t	Wed Jan 16 14:19:28 2013 +0100
@@ -679,16 +679,15 @@
   $ 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'