added web file rename when using svn bug

doc/bugs/Renaming_a_file_via_the_web_is_failing_when_using_subversion.mdwn

@@ -0,0 +1,24 @@
+I'm using ikiwiki 3.12 on Mac OS X (installed via mac ports)
+
+When trying to rename a file via the web interface (using the rename plugin) I get the following error:
+
+Error: Undefined subroutine &IkiWiki::Plugin::svn::dirname called at /opt/local/lib/perl5/vendor_perl/5.8.9/IkiWiki/Plugin/svn.pm line 246.
+
+Applying the following patch fixed it:
+
+    --- IkiWiki/Plugin/svn.pm.orig  2009-07-08 12:25:23.000000000 -0400
+    +++ IkiWiki/Plugin/svn.pm       2009-07-08 12:28:36.000000000 -0400
+    @@ -243,10 +243,10 @@
+     
+            if (-d "$config{srcdir}/.svn") {
+                    # Add parent directory for $dest
+    -               my $parent=dirname($dest);
+    +               my $parent=IkiWiki::dirname($dest);
+                    if (! -d "$config{srcdir}/$parent/.svn") {
+                            while (! -d "$config{srcdir}/$parent/.svn") {
+    -                               $parent=dirname($dest);
+    +                               $parent=Ikiwiki::dirname($dest);
+                            }
+                            if (system("svn", "add", "--quiet", "$config{srcdir}/$parent") != 0) {
+                                    warn("svn add $parent failed\n");
+