fix a bug that doubled the search box

IkiWiki/Wrapper.pm

@@ -47,6 +47,10 @@ EOF
 EOF
 	}
 	
+	# This is only set by plugins, which append to it on startup, so
+	# avoid storing it in the wrapper.
+	$config{headercontent}="";
+	
 	$Data::Dumper::Indent=0; # no newlines
 	my $configstring=Data::Dumper->Dump([\%config], ['*config']);
 	$configstring=~s/\\/\\\\/g;