versionSelector: Pass xml explicitly

Previously, this accessed `$page->xml`, but this is no longer public, so
pass it explicitly.

Author: matthijskooijman

system/core/pages.php

@@ -608,13 +608,13 @@ function wikify_link($node) {
 		Parameters:
 		page - page node from hypha pagelist
 	*/
-	function versionSelector($page) {
-		if ($page->xml->hasVersions()) {
+	function versionSelector($page, $xml) {
+		if ($xml->hasVersions()) {
 			$_action = makeAction($page->language.'/'.$page->pagename, '', 'version');
 			$html = __('version').': '.'<select class="version" name="version" onchange="'.$_action.'">';
 
 			$history = array();
-			foreach($page->xml->getElementById($page->language)->getElementsByTagName('version') as $v) {
+			foreach($xml->getElementById($page->language)->getElementsByTagName('version') as $v) {
 				$timeStamp = $v->getAttribute('xml:id');
 				$history[$timeStamp] = date('j-m-y, H:i', ltrim($timeStamp, 't')).', '.$v->getAttribute('author');
 			}

system/datatypes/text.php

@@ -64,7 +64,7 @@ protected function defaultView(HyphaRequest $request) {
 			// setup addition widgets when client is logged in
 			if (isUser()) {
 				// show a drop down list of revisions
-				$this->html->writeToElement('versionList', versionSelector($this));
+				$this->html->writeToElement('versionList', versionSelector($this, $this->xml));
 
 				// if a revision is selected, show a 'revert' command button
 				if ($version) {