Make sure inner dashboard ids reference to real dashboard attributes

When dashboards are imported from another instance, the inner dashboard ids
in content might be outdated if the referenced inner dashboards do not exist
any more.

This fixes the following error during upgrade:

    Can't use string ... as a HASH ref while "strict refs" in use at etc/upgrade/5.9.1/content line 27

Author: sunnavy

etc/upgrade/5.9.1/content

@@ -23,7 +23,7 @@ our @Final = (
                             $changed ||= 1;
                             my $dashboard = RT::Attribute->new( RT->SystemUser );
                             $dashboard->Load( $portlet->{id} );
-                            if ( $dashboard->Id ) {
+                            if ( $dashboard->Id && $dashboard->Name eq 'Dashboard' ) {
                                 push @new_panes, @{ $dashboard->Content->{'Panes'}{$pane} || [] }
                                     if $dashboard->Content;
                             }