Make our datastream_access call work and revert change to themeing of version links.

islandora.module

@@ -1839,7 +1839,7 @@ function islandora_islandora_datastream_access($op, AbstractDatastream $datastre
     $hooks = islandora_invoke_hook_list(ISLANDORA_DERVIATIVE_CREATION_HOOK, $object->models, array($object));
     foreach ($hooks as $hook) {
       if ($hook['destination_dsid'] == $datastream->id && ((isset($hook['source_dsid']) && isset($object[$hook['source_dsid']]) && islandora_datastream_access(ISLANDORA_VIEW_OBJECTS, $object[$hook['source_dsid']], $user)) || (array_key_exists('source_dsid', $hook) && $hook['source_dsid'] == NULL))) {
-        return TRUE;
+        return user_access(ISLANDORA_REGENERATE_DERIVATIVES);
       }
     }
     return FALSE;

theme/theme.inc

@@ -53,12 +53,14 @@ function islandora_preprocess_islandora_default_edit(array &$variables) {
       'class' => 'datastream-size',
       'data' => islandora_datastream_get_human_readable_size($ds),
     );
-    $row[] = array(
-      'class' => 'datastream-versions',
-      'data' => theme('islandora_datastream_version_link', array(
-        'datastream' => $ds,
-      )),
-    );
+    if (islandora_datastream_access(ISLANDORA_VIEW_DATASTREAM_HISTORY, $ds)) {
+      $row[] = array(
+        'class' => 'datastream-versions',
+        'data' => theme('islandora_datastream_version_link', array(
+          'datastream' => $ds,
+        )),
+      );
+    }
     $row[] = array(
       'class' => 'datastream-download',
       'data' => theme('islandora_datastream_download_link', array(